Merge branch Davi0kProgramsThings:fix/refactoring into branch bitfinexcom:master. (#238)

# Description
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PR includes some global refactoring in preparation for the v3.0.0 stable release.

## Motivation and Context
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-

## Related Issue
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<!--- If fixing a bug, there should be an issue describing it with steps to reproduce -->
<!--- Please link to the issue here: -->
PR fixes the following issue: -

## Type of change
<!-- Select the most suitable choice and remove the others from the checklist -->

- [X] Bug fix (non-breaking change which fixes an issue);

# Checklist:

- [X] I've done a self-review of my code;
- [X] I've made corresponding changes to the documentation;
- [X] I've made sure my changes generate no warnings;
- [X] mypy returns no errors when run on the root package;
<!-- If you use pre-commit hooks you can always check off the following tasks -->
- [X] I've run black to format my code;
- [X] I've run isort to format my code's import statements;
- [X] flake8 reports no errors when run on the entire code base;

bfxapi/types/labeler.py

@@ -24,8 +24,8 @@ def partial(cls):
 
         if len(kwargs) != 0:
             raise TypeError(
-                f"{cls.__name__}.__init__() got an unexpected "
-                "keyword argument '{list(kwargs.keys())[0]}'"
+                f"{cls.__name__}.__init__() got an unexpected keyword argument "
+                f"'{list(kwargs.keys())[0]}'"
             )
 
     cls.__init__ = __init__