def query_one(self, table, columns, where):
    sql = ('SELECT %s FROM %s WHERE %s LIMIT 1' % (columns, table, where))
    self.conn.execute(sql)
    if (self.conn.rowcount == 1):
        return self.conn.fetchone()
    else:
        return None
def query_one(self, table, columns, where):
    sql = ('SELECT %s FROM %s WHERE %s LIMIT 1' % (columns, table, where))
    self.conn.execute(sql)
    if (self.conn.rowcount == 1):
        return self.conn.fetchone()
    else:
        return None