<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def next_location(self, raw=False):
        '''Returns the next location.

        Args:
            raw (bool): If True, the original string contained in the Location
                field will be returned. Otherwise, the URL will be
                normalized to a complete URL.

        Returns:
            str, None: If str, the location. Otherwise, no next location.
        '''
        if self._response:
            location = self._response.fields.get('location')

            if not location or raw:
                return location

            return wpull.url.urljoin(self._response.request.url_info.url,
                                     location)