'Delete data from DB by ID.'

@verify_has_db
def delete(self, _id=None):

    if (_id is None):
        _id = self.id
    sql = (('DELETE    FROM    ' + self._DATA_TABLE) + '    WHERE    id    =    ?    ')
    self._db.execute(sql, (_id,))
    fname = self._get_fname_for_id(_id)
    try:
        os.remove(fname)
    except OSError:
        pass
