Load resource data from server

def _load_resource(self):
        """Load resource data from server"""

        url = self._url
        if self._params:
            url += '?{0}'.format(six.moves.urllib_parse.urlencode(self._params))

        r = getattr(self._session, self._meta.get_method.lower())(url)

        if r.status_code == 404:
            raise NotFoundException('Server returned 404 Not Found for the URL {0}'.format(self._url))
        elif not 200 <= r.status_code < 400:
            raise HTTPException('Server returned {0} ({1})'.format(r.status_code, r.reason), r)

        data = self._meta.deserializer.to_dict(r.text)
        self.populate_field_values(data)