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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def spectrogram(timeseries, method_func, **kwargs):
 """Generate a spectrogram using a method function Each time bin of the resulting spectrogram is a PSD estimate using a single FFT """

    from ...spectrogram import Spectrogram

    # get params
    sampling = timeseries.sample_rate.to('Hz').value
    nproc = kwargs.pop('nproc', 1)
    nfft = kwargs.pop('nfft')
    noverlap = kwargs.pop('noverlap')
    nstride = nfft - noverlap

    # sanity check parameters
    if noverlap >= nfft:
        raise ValueError("overlap must be less than fftlength")

    # set up single process Spectrogram method
    def _psd(series):
        """Calculate a single PSD for a spectrogram
        """
        return method_func(series, nfft=nfft, **kwargs)[1]

    # define chunks
    chunks = []
    x = 0
    while x + nfft <= timeseries.size:
        y = min(timeseries.size, x + nfft)
        chunks.append((x, y))
        x += nstride

    tschunks = (timeseries.value[i:j] for i, j in chunks)

    # calculate PSDs with multiprocessing
    psds = mp_utils.multiprocess_with_queues(nproc, _psd, tschunks)

    # convert PSDs to array with spacing for averages
    numtimes = 1 + int((timeseries.size - nstride) / nstride)
    numfreqs = int(nfft / 2 + 1)
    data = numpy.zeros((numtimes, numfreqs), dtype=timeseries.dtype)
    data[:len(psds)] = psds

    # create output spectrogram
    unit = fft_utils.scale_timeseries_unit(
        timeseries.unit, scaling=kwargs.get('scaling', 'density'))
    out = Spectrogram(numpy.empty((numtimes, numfreqs),
                                  dtype=timeseries.dtype),
                      copy=False, dt=nstride * timeseries.dt, t0=timeseries.t0,
                      f0=0, df=sampling/nfft, unit=unit,
                      name=timeseries.name, channel=timeseries.channel)

    # normalize over-dense grid
    density = nfft // nstride
    weights = get_window('triangle', density)
    for i in range(numtimes):
        # get indices of overlapping columns
        x = max(0, i+1-density)
        y = min(i+1, numtimes-density+1)
        if x == 0:
            wgt = weights[-y:]
        elif y == numtimes - density + 1:
            wgt = weights[:y-x]
        else:
            wgt = weights
        # calculate weighted average
        out.value[i, :] = numpy.average(data[x:y], axis=0, weights=wgt)

    return out