code: def rel_humid_from_db_hr(db_temp, humid_ratio, b_press=101325):
      
      pw = (humid_ratio * 1000 * b_press) / (621.9907 + (humid_ratio * 1000))
      pws = saturated_vapor_pressure(db_temp + 273.15)
      rel_humid = (pw / pws) * 100
      return rel_humid
docs: Relative Humidity (%) at humid_ratio (kg water/kg air), db_temp (C),
      and Pressure b_press (Pa).