code: def _is_whitespace(self, char):
          
          # \t, \n, and \r are technically contorl characters but we treat them
          # as whitespace since they are generally considered as such.
          if char in [' ', '\t', '\n', '\r']:
              return True
          cat = unicodedata.category(char)
          if cat == 'Zs':
              return True
          return False
docs: Checks whether `chars` is a whitespace character.