code: def match_file(self, f, update_file=False):
          
          if self.map_func is not None:
              val = self.map_func(f)
          else:
              m = self.regex.search(f.path)
              val = m.group(1) if m is not None else None
  
          return self._astype(val)
docs: Determine whether the passed file matches the Entity.
  
          Args:
              f (File): The File instance to match against.
  
          Returns: the matched value if a match was found, otherwise None.