Add response headers.

        Add HTTP headers from devil's response to django's response.

def _add_resposne_headers(self, django_response, devil_response):
        """ Add response headers.

        Add HTTP headers from devil's response to django's response.
        """

        try:
            headers = devil_response.headers
        except AttributeError:
            # ok, there was no devil_response
            pass
        else:
            for k, v in headers.items():
                django_response[k] = v
        return django_response