def __init__(self, data, P, Q, lag, NFFT=None, sampling=<NUM_LIT:1.>,<EOL>scale_by_freq=False):
super(parma, self).__init__(data, ma_order=Q, ar_order=P, lag=lag,<EOL>NFFT=NFFT, sampling=sampling,<EOL>scale_by_freq=scale_by_freq)<EOL>self.lag = lag<EOL>
**Constructor:**

        For a detailed description of the parameters, see :func:`arma_estimate`.

        :param array data:     input data (list or numpy.array)
        :param int P:
        :param int Q:
        :param int lag:
        :param int NFFT: total length of the final data sets (padded with
            zero if needed; default is 4096)
        :param float sampling: sampling frequency of the input :attr:`data`.