code: def _dirint_coeffs(times, kt_prime, solar_zenith, w, delta_kt_prime):
      
      kt_prime_bin, zenith_bin, w_bin, delta_kt_prime_bin = \
          _dirint_bins(times, kt_prime, solar_zenith, w, delta_kt_prime)
  
      # get the coefficients
      coeffs = _get_dirint_coeffs()
  
      # subtract 1 to account for difference between MATLAB-style bin
      # assignment and Python-style array lookup.
      dirint_coeffs = coeffs[kt_prime_bin-1, zenith_bin-1,
                             delta_kt_prime_bin-1, w_bin-1]
  
      # convert unassigned bins to nan
      dirint_coeffs = np.where((kt_prime_bin == 0) | (zenith_bin == 0) |
                               (w_bin == 0) | (delta_kt_prime_bin == 0),
                               np.nan, dirint_coeffs)
      return dirint_coeffs
docs: Determine the DISC to DIRINT multiplier `dirint_coeffs`.
  
      dni = disc_out['dni'] * dirint_coeffs
  
      Parameters
      ----------
      times : pd.DatetimeIndex
      kt_prime : Zenith-independent clearness index
      solar_zenith : Solar zenith angle
      w : precipitable water estimated from surface dew-point temperature
      delta_kt_prime : stability index
  
      Returns
      -------
      dirint_coeffs : array-like