Call REST API with RPC force.

        return object: a result

def rpc_call(self, request, method=None, **payload):
        """ Call REST API with RPC force.

        return object: a result

        """
        if not method or self.separator not in method:
            raise AssertionError("Wrong method name: {0}".format(method))

        resource_name, method = method.split(self.separator, 1)
        if resource_name not in self.api.resources:
            raise AssertionError("Unknown method " + method)

        data = QueryDict('', mutable=True)
        data.update(payload.get('data', dict()))
        data['callback'] = payload.get('callback') or request.GET.get(
            'callback') or request.GET.get('jsonp') or 'callback'
        for h, v in payload.get('headers', dict()).iteritems():
            request.META["HTTP_%s" % h.upper().replace('-', '_')] = v

        request.POST = request.PUT = request.GET = data
        delattr(request, '_request')
        request.method = method.upper()
        request.META['CONTENT_TYPE'] = 'application/x-www-form-urlencoded'
        params = payload.pop('params', dict())
        response = self.api.call(resource_name, request, **params)

        if not isinstance(response, SerializedHttpResponse):
            return response

        if response['Content-type'] in self._meta.emitters_dict:
            return HttpResponse(response.content, status=response.status_code)

        if response.status_code == 200:
            return response.response

        raise AssertionError(response.response)