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