Fix black/mypy issues

Author: virtuald

Diff for: cxxheaderparser/preprocessor.py

@@ -341,8 +341,8 @@ def _preprocess_file(filename: str, content: typing.Optional[str]) -> str:
             raise PreprocessorError("retain_all_content and depfile not compatible")
 
         if content is None:
-            with open(filename, "r", encoding=encoding) as fp:
-                content = fp.read()
+            with open(filename, "r", encoding=encoding) as cfp:
+                content = cfp.read()
 
         pp.parse(content, filename)
 

Diff for: tests/test_preprocessor.py

@@ -51,7 +51,7 @@ def make_pp(request) -> typing.Callable[..., PreprocessorFunction]:
 
 
 def test_basic_preprocessor(
-    make_pp: typing.Callable[..., PreprocessorFunction]
+    make_pp: typing.Callable[..., PreprocessorFunction],
 ) -> None:
     content = """
       #define X 1