code: def f_FRD(m1, m2):
      
      m_total, eta = mass1_mass2_to_mtotal_eta(m1, m2)
      tmp = ( (1. - 0.63*(1. - 3.4641016*eta + 2.9*eta**2)**(0.3)) /
      (1. - 0.057191*eta - 0.498*eta**2) )
      return tmp / (2.*lal.PI * m_total*lal.MTSUN_SI)
docs: Fundamental RingDown frequency calculated from the Berti, Cardoso and
      Will (gr-qc/0512160) value for the omega_220 QNM frequency using
      mass-ratio dependent fits to the final BH mass and spin from Buonanno
      et al. (arXiv:0706.3732) : see also InspiralBankGeneration.c
  
      Parameters
      ----------
      m1 : float or numpy.array
          First component mass in solar mass units
      m2 : float or numpy.array
          Second component mass in solar mass units
  
      Returns
      -------
      f : float or numpy.array
          Frequency in Hz