Convert type to BigQuery

def convert_type(self, type):
        """Convert type to BigQuery
        """

        # Mapping
        mapping = {
            'any': 'STRING',
            'array': None,
            'boolean': 'BOOLEAN',
            'date': 'DATE',
            'datetime': 'DATETIME',
            'duration': None,
            'geojson': None,
            'geopoint': None,
            'integer': 'INTEGER',
            'number': 'FLOAT',
            'object': None,
            'string': 'STRING',
            'time': 'TIME',
            'year': 'INTEGER',
            'yearmonth': None,
        }

        # Not supported type
        if type not in mapping:
            message = 'Type %s is not supported' % type
            raise tableschema.exceptions.StorageError(message)

        return mapping[type]