Close this pool connection by releasing the underlying
        :attr:`connection` back to the :attr:`pool`.

def close(self, discard=False):
        '''Close this pool connection by releasing the underlying
        :attr:`connection` back to the :attr:`pool`.
        '''
        if self.pool is not None:
            self.pool._put(self.connection, discard)
            self.pool = None
            conn, self.connection = self.connection, None
            return conn