Drop Py37, improve typing and docstrings (#544)

Drops Py3.7, improves typing and adds a mypy config, improves the docstrings and isorts the imports.

* configure isort
* sort with isort
* add github action
* enable flake8-docstrings
* fix docstrings
* add mypy env
* no implicit optional
* add type for raw
* add some type hints

src/escpos/capabilities.py

@@ -1,20 +1,19 @@
-import re
-from os import environ, path
+"""Handler for capabilities data."""
 import atexit
-import pickle
 import logging
+import pickle
+import platform
+import re
 import time
-import importlib_resources
+from contextlib import ExitStack
+from os import environ, path
+from tempfile import mkdtemp
+from typing import Any, Dict, Optional
 
+import importlib_resources
 import six
 import yaml
 
-from contextlib import ExitStack
-from tempfile import mkdtemp
-import platform
-
-from typing import Any, Dict
-
 logging.basicConfig()
 logger = logging.getLogger(__name__)
 
@@ -60,9 +59,7 @@ PROFILES: Dict[str, Any] = CAPABILITIES["profiles"]
 
 
 class NotSupported(Exception):
-    """Raised if a requested feature is not supported by the
-    printer profile.
-    """
+    """Raised if a requested feature is not supported by the printer profile."""
 
     pass
 
@@ -80,11 +77,13 @@ class BaseProfile(object):
     profile_data: Dict[str, Any] = {}
 
     def __getattr__(self, name):
+        """Get a data element from the profile."""
         return self.profile_data[name]
 
     def get_font(self, font) -> int:
-        """Return the escpos index for `font`. Makes sure that
-        the requested `font` is valid.
+        """Return the escpos index for `font`.
+
+        Makes sure that the requested `font` is valid.
         """
         font = {"a": 0, "b": 1}.get(font, font)
         if not six.text_type(font) in self.fonts:
@@ -107,9 +106,10 @@ class BaseProfile(object):
         return {v: k for k, v in self.codePages.items()}
 
 
-def get_profile(name: str = None, **kwargs):
-    """Get the profile by name; if no name is given, return the
-    default profile.
+def get_profile(name: Optional[str] = None, **kwargs):
+    """Get a profile by name.
+
+    If no name is given, return the default profile.
     """
     if isinstance(name, Profile):
         return name
@@ -122,7 +122,9 @@ CLASS_CACHE = {}
 
 
 def get_profile_class(name: str):
-    """For the given profile name, load the data from the external
+    """Load a profile class.
+
+    For the given profile name, load the data from the external
     database, then generate dynamically a class.
     """
     if name not in CLASS_CACHE:
@@ -136,6 +138,7 @@ def get_profile_class(name: str):
 
 
 def clean(s):
+    """Clean profile name."""
     # Remove invalid characters
     s = re.sub("[^0-9a-zA-Z_]", "", s)
     # Remove leading characters until we find a letter or underscore
@@ -144,17 +147,20 @@ def clean(s):
 
 
 class Profile(get_profile_class("default")):
-    """
-    For users, who want to provide their profile
+    """Profile class for user usage.
+
+    For users, who want to provide their own profile.
     """
 
     def __init__(self, columns=None, features=None):
+        """Initialize profile."""
         super(Profile, self).__init__()
 
         self.columns = columns
         self.features = features or {}
 
     def get_columns(self, font):
+        """Get column count of printer."""
         if self.columns is not None:
             return self.columns