code: def distant_total_damped_rated_level(
              octave_frequencies,
              distance,
              temp,
              relhum,
              reference_distance=1.0):
      
      damping_distance = distance - reference_distance
      sums = 0.0
      for band in OCTAVE_BANDS.keys():
          if band not in octave_frequencies:
              continue
          if octave_frequencies[band] is None:
              continue
          # distance-adjusted level per band
          distant_val = distant_level(
              reference_level=float(octave_frequencies[band]),
              distance=distance,
              reference_distance=reference_distance
          )
          # damping
          damp_per_meter = damping(
              temp=temp,
              relhum=relhum,
              freq=OCTAVE_BANDS[band][0])
          distant_val = distant_val - (damping_distance * damp_per_meter)
          # applyng A-rating
          distant_val += OCTAVE_BANDS[band][1]
          sums += pow(10.0, (distant_val / 10.0))
      level = 10.0 * math.log10(sums)
      return level
docs: Calculates the damped, A-rated total sound pressure level
      in a given distance, temperature and relative humidity
      from octave frequency sound pressure levels in a reference distance