code: def get_mass_spin(bank, tid):
      
      m1 = bank['mass1'][:][tid]
      m2 = bank['mass2'][:][tid]
      s1z = bank['spin1z'][:][tid]
      s2z = bank['spin2z'][:][tid]
      return m1, m2, s1z, s2z
docs: Helper function
  
      Parameters
      ----------
      bank : h5py File object
          Bank parameter file
      tid : integer or array of int
          Indices of the entries to be returned
  
      Returns
      -------
      m1, m2, s1z, s2z : tuple of floats or arrays of floats
          Parameter values of the bank entries