code: def rough_time_estimate(m1, m2, flow, fudge_length=1.1, fudge_min=0.02):
      
      m = m1 + m2
      msun = m * lal.MTSUN_SI
      t =  5.0 / 256.0 * m * m * msun / (m1 * m2) / \
          (numpy.pi * msun * flow) **  (8.0 / 3.0)
  
      # fudge factoriness
      return .022 if t < 0 else (t + fudge_min) * fudge_length
docs: A very rough estimate of the duration of the waveform.
  
      An estimate of the waveform duration starting from flow. This is intended
      to be fast but not necessarily accurate. It should be an overestimate of
      the length. It is derived from a simplification of the 0PN post-newtonian
      terms and includes a fudge factor for possible ringdown, etc.
  
      Parameters
      ----------
      m1: float
          mass of first component object in solar masses
      m2: float
          mass of second component object in solar masses
      flow: float
          starting frequency of the waveform
      fudge_length: optional, {1.1, float}
          Factor to multiply length estimate by to ensure it is a convservative
          value
      fudge_min: optional, {0.2, float}
          Minimum signal duration that can be returned. This should be long
          enough to encompass the ringdown and errors in the precise end time.
  
      Returns
      -------
      time: float
          Time from flow untill the end of the waveform