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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 spa_length_in_time(**kwds):
 """ Returns the length in time of the template, based on the masses, PN order, and low-frequency cut-off. """

    m1 = kwds['mass1']
    m2 = kwds['mass2']
    flow = kwds['f_lower']
    porder = int(kwds['phase_order'])

    # For now, we call the swig-wrapped function below in
    # lalinspiral.  Eventually would be nice to replace this
    # with a function using PN coeffs from lalsimulation.
    return findchirp_chirptime(m1, m2, flow, porder)