Optional cuz of mypy

Author: barabum0

devtools/debug.py

@@ -108,7 +108,7 @@ def __repr__(self) -> StrType:
 class Debug:
     output_class = DebugOutput
 
-    def __init__(self, *, warnings: 'Optional[bool]' = None, highlight: 'Optional[bool]' = None, logger_function: 'Callable[[str], None]' = None):
+    def __init__(self, *, warnings: 'Optional[bool]' = None, highlight: 'Optional[bool]' = None, logger_function: 'Optional[Callable[[str], None]]' = None):
         self._show_warnings = env_bool(warnings, 'PY_DEVTOOLS_WARNINGS', True)
         self._highlight = highlight
         self._logger_function = logger_function