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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_name_from_url(self, request):
 """ Determine short name for the mapper based on the URL. Short name can be either in query string (e.g. ?format=json) or as an extension to the URL (e.g. myresource.json). :returns: short name of the mapper or ``None`` if not found. """


        format = request.GET.get('format', None)
        if not format:
            match = self._format_query_pattern.match(request.path)
            if match and match.group('format'):
                format = match.group('format')
        return format