From 9cc0e2be505feed23420349cb7eb7b4b24cb2181 Mon Sep 17 00:00:00 2001
From: Florian Brandes <florian.brandes@posteo.de>
Date: Fri, 5 Jul 2024 12:41:22 +0200
Subject: [PATCH] fix pylint issues

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>
---
 .pylintrc  | 639 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 devenv.nix |   2 +-
 smtprd.py  | 107 +++++++--
 3 files changed, 727 insertions(+), 21 deletions(-)
 create mode 100644 .pylintrc

diff --git a/.pylintrc b/.pylintrc
new file mode 100644
index 0000000..e558e66
--- /dev/null
+++ b/.pylintrc
@@ -0,0 +1,639 @@
+[MAIN]
+
+# Analyse import fallback blocks. This can be used to support both Python 2 and
+# 3 compatible code, which means that the block might have code that exists
+# only in one or another interpreter, leading to false positives when analysed.
+analyse-fallback-blocks=no
+
+# Clear in-memory caches upon conclusion of linting. Useful if running pylint
+# in a server-like mode.
+clear-cache-post-run=no
+
+# Load and enable all available extensions. Use --list-extensions to see a list
+# all available extensions.
+#enable-all-extensions=
+
+# In error mode, messages with a category besides ERROR or FATAL are
+# suppressed, and no reports are done by default. Error mode is compatible with
+# disabling specific errors.
+#errors-only=
+
+# Always return a 0 (non-error) status code, even if lint errors are found.
+# This is primarily useful in continuous integration scripts.
+#exit-zero=
+
+# A comma-separated list of package or module names from where C extensions may
+# be loaded. Extensions are loading into the active Python interpreter and may
+# run arbitrary code.
+extension-pkg-allow-list=
+
+# A comma-separated list of package or module names from where C extensions may
+# be loaded. Extensions are loading into the active Python interpreter and may
+# run arbitrary code. (This is an alternative name to extension-pkg-allow-list
+# for backward compatibility.)
+extension-pkg-whitelist=
+
+# Return non-zero exit code if any of these messages/categories are detected,
+# even if score is above --fail-under value. Syntax same as enable. Messages
+# specified are enabled, while categories only check already-enabled messages.
+fail-on=
+
+# Specify a score threshold under which the program will exit with error.
+fail-under=10
+
+# Interpret the stdin as a python script, whose filename needs to be passed as
+# the module_or_package argument.
+#from-stdin=
+
+# Files or directories to be skipped. They should be base names, not paths.
+ignore=CVS
+
+# Add files or directories matching the regular expressions patterns to the
+# ignore-list. The regex matches against paths and can be in Posix or Windows
+# format. Because '\\' represents the directory delimiter on Windows systems,
+# it can't be used as an escape character.
+ignore-paths=
+
+# Files or directories matching the regular expression patterns are skipped.
+# The regex matches against base names, not paths. The default value ignores
+# Emacs file locks
+ignore-patterns=^\.#
+
+# List of module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis). It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=
+
+# Python code to execute, usually for sys.path manipulation such as
+# pygtk.require().
+# this will add the .venv packages, so pylint can find them
+init-hook='import sys; import os; sys.path.append(os.path.join(os.getcwd(), ".devenv", "state", "venv", "lib", "python3.11", "site-packages"))'
+
+# Use multiple processes to speed up Pylint. Specifying 0 will auto-detect the
+# number of processors available to use, and will cap the count on Windows to
+# avoid hangs.
+jobs=1
+
+# Control the amount of potential inferred values when inferring a single
+# object. This can help the performance when dealing with large functions or
+# complex, nested conditions.
+limit-inference-results=100
+
+# List of plugins (as comma separated values of python module names) to load,
+# usually to register additional checkers.
+load-plugins=
+
+# Pickle collected data for later comparisons.
+persistent=yes
+
+# Minimum Python version to use for version dependent checks. Will default to
+# the version used to run pylint.
+py-version=3.11
+
+# Discover python modules and packages in the file system subtree.
+recursive=no
+
+# Add paths to the list of the source roots. Supports globbing patterns. The
+# source root is an absolute path or a path relative to the current working
+# directory used to determine a package namespace for modules located under the
+# source root.
+source-roots=
+
+# When enabled, pylint would attempt to guess common misconfiguration and emit
+# user-friendly hints instead of false-positive error messages.
+suggestion-mode=yes
+
+# Allow loading of arbitrary C extensions. Extensions are imported into the
+# active Python interpreter and may run arbitrary code.
+unsafe-load-any-extension=no
+
+# In verbose mode, extra non-checker-related info will be displayed.
+#verbose=
+
+
+[BASIC]
+
+# Naming style matching correct argument names.
+argument-naming-style=snake_case
+
+# Regular expression matching correct argument names. Overrides argument-
+# naming-style. If left empty, argument names will be checked with the set
+# naming style.
+#argument-rgx=
+
+# Naming style matching correct attribute names.
+attr-naming-style=snake_case
+
+# Regular expression matching correct attribute names. Overrides attr-naming-
+# style. If left empty, attribute names will be checked with the set naming
+# style.
+#attr-rgx=
+
+# Bad variable names which should always be refused, separated by a comma.
+bad-names=foo,
+          bar,
+          baz,
+          toto,
+          tutu,
+          tata
+
+# Bad variable names regexes, separated by a comma. If names match any regex,
+# they will always be refused
+bad-names-rgxs=
+
+# Naming style matching correct class attribute names.
+class-attribute-naming-style=any
+
+# Regular expression matching correct class attribute names. Overrides class-
+# attribute-naming-style. If left empty, class attribute names will be checked
+# with the set naming style.
+#class-attribute-rgx=
+
+# Naming style matching correct class constant names.
+class-const-naming-style=UPPER_CASE
+
+# Regular expression matching correct class constant names. Overrides class-
+# const-naming-style. If left empty, class constant names will be checked with
+# the set naming style.
+#class-const-rgx=
+
+# Naming style matching correct class names.
+class-naming-style=PascalCase
+
+# Regular expression matching correct class names. Overrides class-naming-
+# style. If left empty, class names will be checked with the set naming style.
+#class-rgx=
+
+# Naming style matching correct constant names.
+const-naming-style=UPPER_CASE
+
+# Regular expression matching correct constant names. Overrides const-naming-
+# style. If left empty, constant names will be checked with the set naming
+# style.
+#const-rgx=
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=-1
+
+# Naming style matching correct function names.
+function-naming-style=snake_case
+
+# Regular expression matching correct function names. Overrides function-
+# naming-style. If left empty, function names will be checked with the set
+# naming style.
+#function-rgx=
+
+# Good variable names which should always be accepted, separated by a comma.
+good-names=i,
+           j,
+           k,
+           ex,
+           Run,
+           _
+
+# Good variable names regexes, separated by a comma. If names match any regex,
+# they will always be accepted
+good-names-rgxs=
+
+# Include a hint for the correct naming format with invalid-name.
+include-naming-hint=no
+
+# Naming style matching correct inline iteration names.
+inlinevar-naming-style=any
+
+# Regular expression matching correct inline iteration names. Overrides
+# inlinevar-naming-style. If left empty, inline iteration names will be checked
+# with the set naming style.
+#inlinevar-rgx=
+
+# Naming style matching correct method names.
+method-naming-style=snake_case
+
+# Regular expression matching correct method names. Overrides method-naming-
+# style. If left empty, method names will be checked with the set naming style.
+#method-rgx=
+
+# Naming style matching correct module names.
+module-naming-style=snake_case
+
+# Regular expression matching correct module names. Overrides module-naming-
+# style. If left empty, module names will be checked with the set naming style.
+#module-rgx=
+
+# Colon-delimited sets of names that determine each other's naming style when
+# the name regexes allow several styles.
+name-group=
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=^_
+
+# List of decorators that produce properties, such as abc.abstractproperty. Add
+# to this list to register other decorators that produce valid properties.
+# These decorators are taken in consideration only for invalid-name.
+property-classes=abc.abstractproperty
+
+# Regular expression matching correct type alias names. If left empty, type
+# alias names will be checked with the set naming style.
+#typealias-rgx=
+
+# Regular expression matching correct type variable names. If left empty, type
+# variable names will be checked with the set naming style.
+#typevar-rgx=
+
+# Naming style matching correct variable names.
+variable-naming-style=snake_case
+
+# Regular expression matching correct variable names. Overrides variable-
+# naming-style. If left empty, variable names will be checked with the set
+# naming style.
+#variable-rgx=
+
+
+[CLASSES]
+
+# Warn about protected attribute access inside special methods
+check-protected-access-in-special-methods=no
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,
+                      __new__,
+                      setUp,
+                      asyncSetUp,
+                      __post_init__
+
+# List of member names, which should be excluded from the protected access
+# warning.
+exclude-protected=_asdict,_fields,_replace,_source,_make,os._exit
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=mcs
+
+
+[DESIGN]
+
+# List of regular expressions of class ancestor names to ignore when counting
+# public methods (see R0903)
+exclude-too-few-public-methods=
+
+# List of qualified class names to ignore when counting class parents (see
+# R0901)
+ignored-parents=
+
+# Maximum number of arguments for function / method.
+max-args=5
+
+# Maximum number of attributes for a class (see R0902).
+max-attributes=7
+
+# Maximum number of boolean expressions in an if statement (see R0916).
+max-bool-expr=5
+
+# Maximum number of branch for function / method body.
+max-branches=12
+
+# Maximum number of locals for function / method body.
+max-locals=15
+
+# Maximum number of parents for a class (see R0901).
+max-parents=7
+
+# Maximum number of public methods for a class (see R0904).
+max-public-methods=20
+
+# Maximum number of return / yield for function / method body.
+max-returns=6
+
+# Maximum number of statements in function / method body.
+max-statements=50
+
+# Minimum number of public methods for a class (see R0903).
+min-public-methods=2
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when caught.
+overgeneral-exceptions=builtins.BaseException,builtins.Exception
+
+
+[FORMAT]
+
+# Expected format of line ending, e.g. empty (any line ending), LF or CRLF.
+expected-line-ending-format=
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=^\s*(# )?<?https?://\S+>?$
+
+# Number of spaces of indent required inside a hanging or continued line.
+indent-after-paren=4
+
+# String used as indentation unit. This is usually "    " (4 spaces) or "\t" (1
+# tab).
+indent-string='    '
+
+# Maximum number of characters on a single line.
+max-line-length=115
+
+# Maximum number of lines in a module.
+max-module-lines=1000
+
+# Allow the body of a class to be on the same line as the declaration if body
+# contains single statement.
+single-line-class-stmt=no
+
+# Allow the body of an if to be on the same line as the test if there is no
+# else.
+single-line-if-stmt=no
+
+
+[IMPORTS]
+
+# List of modules that can be imported at any level, not just the top level
+# one.
+allow-any-import-level=
+
+# Allow explicit reexports by alias from a package __init__.
+allow-reexport-from-package=no
+
+# Allow wildcard imports from modules that define __all__.
+allow-wildcard-with-all=no
+
+# Deprecated modules which should not be used, separated by a comma.
+deprecated-modules=
+
+# Output a graph (.gv or any supported image format) of external dependencies
+# to the given file (report RP0402 must not be disabled).
+ext-import-graph=
+
+# Output a graph (.gv or any supported image format) of all (i.e. internal and
+# external) dependencies to the given file (report RP0402 must not be
+# disabled).
+import-graph=
+
+# Output a graph (.gv or any supported image format) of internal dependencies
+# to the given file (report RP0402 must not be disabled).
+int-import-graph=
+
+# Force import order to recognize a module as part of the standard
+# compatibility libraries.
+known-standard-library=
+
+# Force import order to recognize a module as part of a third party library.
+known-third-party=enchant
+
+# Couples of modules and preferred modules, separated by a comma.
+preferred-modules=
+
+
+[LOGGING]
+
+# The type of string formatting that logging methods do. `old` means using %
+# formatting, `new` is for `{}` formatting.
+logging-format-style=old
+
+# Logging modules to check that the string format arguments are in logging
+# function parameter format.
+logging-modules=logging
+
+
+[MESSAGES CONTROL]
+
+# Only show warnings with the listed confidence levels. Leave empty to show
+# all. Valid levels: HIGH, CONTROL_FLOW, INFERENCE, INFERENCE_FAILURE,
+# UNDEFINED.
+confidence=HIGH,
+           CONTROL_FLOW,
+           INFERENCE,
+           INFERENCE_FAILURE,
+           UNDEFINED
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once). You can also use "--disable=all" to
+# disable everything first and then re-enable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use "--disable=all --enable=classes
+# --disable=W".
+disable=raw-checker-failed,
+        bad-inline-option,
+        locally-disabled,
+        file-ignored,
+        suppressed-message,
+        useless-suppression,
+        deprecated-pragma,
+        use-symbolic-message-instead,
+        use-implicit-booleaness-not-comparison-to-string,
+        use-implicit-booleaness-not-comparison-to-zero
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time (only on the command line, not in the configuration file where
+# it should appear only once). See also the "--disable" option for examples.
+enable=
+
+
+[METHOD_ARGS]
+
+# List of qualified names (i.e., library.method) which require a timeout
+# parameter e.g. 'requests.api.get,requests.api.post'
+timeout-methods=requests.api.delete,requests.api.get,requests.api.head,requests.api.options,requests.api.patch,requests.api.post,requests.api.put,requests.api.request
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=FIXME,
+      XXX
+
+# Regular expression of note tags to take in consideration.
+notes-rgx=
+
+
+[REFACTORING]
+
+# Maximum number of nested blocks for function / method body
+max-nested-blocks=5
+
+# Complete name of functions that never returns. When checking for
+# inconsistent-return-statements if a never returning function is called then
+# it will be considered as an explicit return statement and no message will be
+# printed.
+never-returning-functions=sys.exit,argparse.parse_error
+
+# Let 'consider-using-join' be raised when the separator to join on would be
+# non-empty (resulting in expected fixes of the type: ``"- " + " -
+# ".join(items)``)
+suggest-join-with-non-empty-separator=yes
+
+
+[REPORTS]
+
+# Python expression which should return a score less than or equal to 10. You
+# have access to the variables 'fatal', 'error', 'warning', 'refactor',
+# 'convention', and 'info' which contain the number of messages in each
+# category, as well as 'statement' which is the total number of statements
+# analyzed. This score is used by the global evaluation report (RP0004).
+evaluation=max(0, 0 if fatal else 10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10))
+
+# Template used to display messages. This is a python new-style format string
+# used to format the message information. See doc for all details.
+msg-template=
+
+# Set the output format. Available formats are: text, parseable, colorized,
+# json2 (improved json format), json (old json format) and msvs (visual
+# studio). You can also give a reporter class, e.g.
+# mypackage.mymodule.MyReporterClass.
+#output-format=
+
+# Tells whether to display a full report or only the messages.
+reports=no
+
+# Activate the evaluation score.
+score=yes
+
+
+[SIMILARITIES]
+
+# Comments are removed from the similarity computation
+ignore-comments=yes
+
+# Docstrings are removed from the similarity computation
+ignore-docstrings=yes
+
+# Imports are removed from the similarity computation
+ignore-imports=yes
+
+# Signatures are removed from the similarity computation
+ignore-signatures=yes
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+
+[SPELLING]
+
+# Limits count of emitted suggestions for spelling mistakes.
+max-spelling-suggestions=4
+
+# Spelling dictionary name. No available dictionaries : You need to install
+# both the python package and the system dependency for enchant to work.
+spelling-dict=
+
+# List of comma separated words that should be considered directives if they
+# appear at the beginning of a comment and should not be checked.
+spelling-ignore-comment-directives=fmt: on,fmt: off,noqa:,noqa,nosec,isort:skip,mypy:
+
+# List of comma separated words that should not be checked.
+spelling-ignore-words=
+
+# A path to a file that contains the private dictionary; one word per line.
+spelling-private-dict-file=
+
+# Tells whether to store unknown words to the private dictionary (see the
+# --spelling-private-dict-file option) instead of raising a message.
+spelling-store-unknown-words=no
+
+
+[STRING]
+
+# This flag controls whether inconsistent-quotes generates a warning when the
+# character used as a quote delimiter is used inconsistently within a module.
+check-quote-consistency=no
+
+# This flag controls whether the implicit-str-concat should generate a warning
+# on implicit string concatenation in sequences defined over several lines.
+check-str-concat-over-line-jumps=no
+
+
+[TYPECHECK]
+
+# List of decorators that produce context managers, such as
+# contextlib.contextmanager. Add to this list to register other decorators that
+# produce valid context managers.
+contextmanager-decorators=contextlib.contextmanager
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E1101 when accessed. Python regular
+# expressions are accepted.
+generated-members=
+
+# Tells whether to warn about missing members when the owner of the attribute
+# is inferred to be None.
+ignore-none=yes
+
+# This flag controls whether pylint should warn about no-member and similar
+# checks whenever an opaque object is returned when inferring. The inference
+# can return multiple potential results while evaluating a Python object, but
+# some branches might not be evaluated, which results in partial inference. In
+# that case, it might be useful to still emit no-member and other checks for
+# the rest of the inferred objects.
+ignore-on-opaque-inference=yes
+
+# List of symbolic message names to ignore for Mixin members.
+ignored-checks-for-mixins=no-member,
+                          not-async-context-manager,
+                          not-context-manager,
+                          attribute-defined-outside-init
+
+# List of class names for which member attributes should not be checked (useful
+# for classes with dynamically set attributes). This supports the use of
+# qualified names.
+ignored-classes=optparse.Values,thread._local,_thread._local,argparse.Namespace
+
+# Show a hint with possible names when a member name was not found. The aspect
+# of finding the hint is based on edit distance.
+missing-member-hint=yes
+
+# The minimum edit distance a name should have in order to be considered a
+# similar match for a missing member name.
+missing-member-hint-distance=1
+
+# The total number of similar names that should be taken in consideration when
+# showing a hint for a missing member.
+missing-member-max-choices=1
+
+# Regex pattern to define which classes are considered mixins.
+mixin-class-rgx=.*[Mm]ixin
+
+# List of decorators that change the signature of a decorated function.
+signature-mutators=
+
+
+[VARIABLES]
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid defining new builtins when possible.
+additional-builtins=
+
+# Tells whether unused global variables should be treated as a violation.
+allow-global-unused-variables=yes
+
+# List of names allowed to shadow builtins
+allowed-redefined-builtins=
+
+# List of strings which can identify a callback function by name. A callback
+# name must start or end with one of those strings.
+callbacks=cb_,
+          _cb
+
+# A regular expression matching the name of dummy variables (i.e. expected to
+# not be used).
+dummy-variables-rgx=_+$|(_[a-zA-Z0-9_]*[a-zA-Z0-9]+?$)|dummy|^ignored_|^unused_
+
+# Argument names that match this expression will be ignored.
+ignored-argument-names=_.*|^ignored_|^unused_
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# List of qualified module names which can have objects that can redefine
+# builtins.
+redefining-builtins-modules=six.moves,past.builtins,future.builtins,builtins,io
diff --git a/devenv.nix b/devenv.nix
index 393a24d..72b3f9c 100644
--- a/devenv.nix
+++ b/devenv.nix
@@ -51,7 +51,7 @@
     # same profile for black and isort
     isort.settings.flags = "--profile black";
     # look for code smell
-    # pylint.enable = true;
+    pylint.enable = true;
     detect-private-keys.enable = true;
 
 
diff --git a/smtprd.py b/smtprd.py
index 02f919c..cf7ef9e 100644
--- a/smtprd.py
+++ b/smtprd.py
@@ -33,17 +33,22 @@ from cryptography.hazmat.primitives.serialization import (
     pkcs7,
 )
 from cryptography.x509 import load_pem_x509_certificate
-from envelope import Envelope
+from envelope import Envelope as EnvelopeEnvelope
 
 
 @dataclass(frozen=True)
 class ServerConfig:
+    """Serverconfig"""
+
     hostname: str
     port: int
 
 
+# pylint: disable=too-many-instance-attributes
 @dataclass(frozen=True)
 class ClientConfig:
+    """Clientconfig"""
+
     hostname: str
     port: int
     sender: str
@@ -60,6 +65,13 @@ class ClientConfig:
 
 @dataclass(frozen=True)
 class Config:
+    """Config main module
+
+    Raises:
+        RuntimeError: When config file cannot be parsed
+
+    """
+
     server: ServerConfig
     client: ClientConfig
 
@@ -94,9 +106,20 @@ class Config:
 
     @classmethod
     def from_ini(cls, filename: str) -> "Config":
+        """Opens and reads .INI config file
+
+        Args:
+            filename (str): config file path
+
+        Raises:
+            RuntimeError: on error in config file
+
+        Returns:
+            Config: ConfigParser object
+        """
         try:
             config_parser: configparser.ConfigParser = configparser.ConfigParser()
-            with open(filename, "r") as fp:
+            with open(filename, "r", encoding="utf8") as fp:
                 config_parser.read_file(fp)
             return cls._from_config(config_parser)
         except (OSError, configparser.Error, UnicodeDecodeError) as e:
@@ -104,6 +127,12 @@ class Config:
 
 
 class SMTPClient(SMTP):
+    """Client part of library
+
+    This will connect to an upstream SMTP server to deliver the mal
+
+    """
+
     def __init__(self, config: ClientConfig) -> None:
         self._config: ClientConfig = config
         self._lock: asyncio.Lock = asyncio.Lock()
@@ -116,10 +145,10 @@ class SMTPClient(SMTP):
             start_tls=self._config.start_tls,
         )
 
-    def _encrypt_and_sign(self, message: Message, recipients: List[str]) -> Message:
+    def _encrypt_and_sign(self, message: Message) -> Message:
         # Currently does NOT work
         new_message = (
-            Envelope()
+            EnvelopeEnvelope()
             .smime()
             .load(message)
             .sign(
@@ -168,8 +197,8 @@ class SMTPClient(SMTP):
     ) -> None:
         # if we use send_message, it expects a message object
         # This will add a newline after the signing process. The message object is fine
-        # but as soon as _as_bytes or _as_string is called, it will add a new line between the boundary of the
-        # signed message, which will ruin the signature
+        # but as soon as _as_bytes or _as_string is called, it will add a new line
+        # between the boundary of the signed message, which will ruin the signature
         failed_recipients: Set[str] = set(
             (
                 await self.sendmail(
@@ -179,7 +208,7 @@ class SMTPClient(SMTP):
                 )
             )[0].keys()
         )
-        if len(failed_recipients):  # raise also when not all have been refused
+        if len(failed_recipients) > 0:  # raise also when not all have been refused
             raise SMTPRecipientsRefused(
                 [SMTPRecipientRefused(0, "", _) for _ in failed_recipients]
             )
@@ -187,6 +216,18 @@ class SMTPClient(SMTP):
     async def forward_message(
         self, message: Message, sender: Optional[str], recipients: List[str]
     ) -> None:
+        """Modify message to be passed on.
+
+        Remove original From, To and Reply-To and replace with "Original-X" header.
+        Call _sign function, if there is a cert saved in the config.
+        Pass it on to the actual send function
+
+        Args:
+            message (Message): message
+            sender (Optional[str]): Original sender
+            recipients (List[str]): Original recipients
+
+        """
         del message["From"]
         del message["To"]
         del message["Reply-To"]
@@ -216,13 +257,30 @@ class SMTPClient(SMTP):
                 self.close()
 
 
+# pylint: disable=too-few-public-methods
 class Handler:
+    """Reimplement Handler"""
+
     def __init__(self, client: SMTPClient) -> None:
+        """Impelent our SMTPClient"""
         self._client: SMTPClient = client
 
-    async def handle_DATA(
-        self, server: Server, session: Session, envelope: Envelope
+    async def handle_DATA(  # pylint: disable=invalid-name
+        self,
+        server: Server,
+        session: Session,  # pylint: disable=unused-argument
+        envelope: Envelope,
     ) -> str:
+        """Forward the message from our server to our client function
+
+        Args:
+            server (Server): Our server
+            session (Session): Current session (Not used here)
+            envelope (Envelope): message envelope
+
+        Returns:
+            str: Status to client
+        """
         try:
             await self._client.forward_message(
                 self._prepare_message(server, envelope),
@@ -232,17 +290,15 @@ class Handler:
         except (RuntimeError, ValueError) as e:
             print(f"Cannot forward: {str(e)}", file=sys.stderr)
             return f"550 {e.__cause__.__class__.__name__ if e.__cause__ is not None else e.__class__.__name__}"
-        else:
-            return "250 OK"
+        return "250 OK"
 
     @classmethod
     def _parse_message(cls, data: Optional[Union[bytes, str]]) -> Message:
         if isinstance(data, bytes):
             return message_from_bytes(data, policy=EmailMessagePolicy)
-        elif isinstance(data, str):
+        if isinstance(data, str):
             return message_from_string(data, policy=EmailMessagePolicy)
-        else:
-            raise ValueError(str(type(data)))
+        raise ValueError(str(type(data)))
 
     def _prepare_message(self, server: Server, envelope: Envelope) -> Message:
         message: Message = self._parse_message(envelope.content)
@@ -267,6 +323,8 @@ class Handler:
 
 
 class SMTPServer(Controller):
+    """Implementation of local SMTP Server Controller"""
+
     def __init__(self, config: ServerConfig, handler: Handler) -> None:
         super().__init__(
             handler=handler,
@@ -276,9 +334,14 @@ class SMTPServer(Controller):
         )
 
     def run(self) -> bool:
+        """Run routine
+
+        Returns:
+            bool: True on finished routine
+        """
         shutdown_requested: threading.Event = threading.Event()
 
-        def _handler(signum: int, frame) -> None:
+        def _handler(signum: int, frame) -> None:  # pylint: disable=unused-argument
             shutdown_requested.set()
 
         signal.signal(signal.SIGINT, _handler)
@@ -293,6 +356,11 @@ class SMTPServer(Controller):
 
 
 def main() -> int:
+    """Main routine
+
+    Returns:
+        int: exit code
+    """
     parser = argparse.ArgumentParser(
         description=__doc__.strip(),
         formatter_class=argparse.ArgumentDefaultsHelpFormatter,
@@ -312,11 +380,10 @@ def main() -> int:
     except RuntimeError as e:
         print(str(e), file=sys.stderr)
         return 1
-    else:
-        controller = SMTPServer(
-            config=config.server, handler=Handler(SMTPClient(config.client))
-        )
-        return 0 if controller.run() else 1
+    controller = SMTPServer(
+        config=config.server, handler=Handler(SMTPClient(config.client))
+    )
+    return 0 if controller.run() else 1
 
 
 if __name__ == "__main__":