Find the responses corresponding to a request.
        This function isn't actually used by VCR internally, but is
        provided as an external API.

def responses_of(self, request):
        """
        Find the responses corresponding to a request.
        This function isn't actually used by VCR internally, but is
        provided as an external API.
        """
        responses = [response for index, response in self._responses(request)]

        if responses:
            return responses
        # The cassette doesn't contain the request asked for.
        raise UnhandledHTTPRequestError(
            "The cassette (%r) doesn't contain the request (%r) asked for"
            % (self._path, request)
        )