def featuretypes(self):
        """
        Iterate over feature types found in the database.

        Returns
        -------
        A generator object that yields featuretypes (as strings)
        """
        c = self.conn.cursor()
        c.execute(
            '''
            SELECT DISTINCT featuretype from features
            ''')
        for i, in c:
            yield i
Iterate over feature types found in the database.

        Returns
        -------
        A generator object that yields featuretypes (as strings)