refactor set method (#547)

* add type annotations
* Update setup.cfg
* improve mypy and test config
* get_profile_class returns a baseProfile
* mute mypy type issue
* add set_with_default
* docstring
* add test for empty call
* correct type annotations in set_with_default
* improve tests
* test for exception
* sort with isort
* add default value to get call
* empty string has the same effect: will not be found --> None
* add mypy test to workflow
* explicitely call mypy
* update spelling

src/escpos/capabilities.py

@@ -8,7 +8,7 @@ import time
 from contextlib import ExitStack
 from os import environ, path
 from tempfile import mkdtemp
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Optional, Type
 
 import importlib_resources
 import six
@@ -148,7 +148,7 @@ def get_profile(name: Optional[str] = None, **kwargs):
 CLASS_CACHE = {}
 
 
-def get_profile_class(name: str):
+def get_profile_class(name: str) -> Type[BaseProfile]:
     """Load a profile class.
 
     For the given profile name, load the data from the external
@@ -174,7 +174,11 @@ def clean(s):
     return str(s)
 
 
-class Profile(get_profile_class("default")):
+# mute the mypy type issue with this dynamic base class function for now (: Any)
+ProfileBaseClass: Any = get_profile_class("default")
+
+
+class Profile(ProfileBaseClass):
     """Profile class for user usage.
 
     For users, who want to provide their own profile.