def text_search(self, anchor, byte=False):
        """
        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.
        """

        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')
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.