docs: def is_valid_pep484_type_hint(typ_hint, allow_forward_refs: bool = False):
      """
      Returns True if the provided type is a valid PEP484 type hint, False otherwise.
  
      Note: string type hints (forward references) are not supported by default, since callers of this function in
      parsyfiles lib actually require them to be resolved already.
  
      :param typ_hint:
      :param allow_forward_refs:
      :return:
      """
      # most common case first, to be faster
      try:
          if isinstance(typ_hint, type):
              return True
      except:
          pass
  
      # optionally, check forward reference
      try:
          if allow_forward_refs and is_forward_ref(typ_hint):
              return True
      except:
          pass
  
      # finally check unions and typevars
      try:
          return is_union_type(typ_hint) or is_typevar(typ_hint)
      except:
          return False