code: def dew_point_from_db_rh(db_temp, rh):
      
      es = 6.112 * math.e**((17.67 * db_temp) / (db_temp + 243.5))
      e = (es * rh) / 100
      td = (243.5 * math.log(e / 6.112)) / (17.67 - math.log(e / 6.112))
      return td
docs: Dew Point Temperature (C) at Dry Bulb Temperature db_temp (C) and
      Relative Humidity rh (%).
  
      Note:
          [1] J. Sullivan and L. D. Sanders. "Method for obtaining wet-bulb temperatures by
          modifying the psychrometric formula." Center for Experiment Design and Data
          Analysis. NOAA - National Oceanic and Atmospheric Administration.
          http://www.srh.noaa.gov/epz/?n=wxcalc_rh