[Code Cleanup] Format source files with black

README.rst

@@ -39,6 +39,12 @@ Static linting:
 
    poetry run pylint earthsnake tests
 
+Code style check:
+
+.. code-block:: sh
+
+   poetry run black --diff --skip-string-normalization earthsnake tests
+
 Tests:
 
 .. code-block:: sh