--- /dev/null
+from typing import Any, Pattern
+
+from .compat import tobytes as tobytes
+
+WS: str
+OWS: str
+RWS: str
+BWS = str
+TCHAR: str
+OBS_TEXT: str
+TOKEN: str
+VCHAR: str
+FIELD_VCHAR: str
+FIELD_CONTENT: str
+FIELD_VALUE: str
+HEADER_FIELD: Pattern[Any]