code: def text_search(self, anchor, byte=False):
          
  
          if isinstance(anchor, six.text_type):
              if byte:
                  raise GrabMisuseError('The anchor should be bytes string in '
                                        'byte mode')
              else:
                  return anchor in self.unicode_body()
  
          if not isinstance(anchor, six.text_type):
              if byte:
                  # if six.PY3:
                      # return anchor in self.body_as_bytes()
                  return anchor in self.body
              else:
                  raise GrabMisuseError('The anchor should be byte string in '
                                        'non-byte mode')
docs: Search the substring in response body.
  
          :param anchor: string to search
          :param byte: if False then `anchor` should be the
              unicode string, and search will be performed in
              `response.unicode_body()` else `anchor` should be the byte-string
              and search will be performed in `response.body`
  
          If substring is found return True else False.