code: def _calculate_degree_days(temperature_equivalent, base_temperature, cooling=False):
      
  
      if cooling:
          ret = temperature_equivalent - base_temperature
      else:
          ret = base_temperature - temperature_equivalent
  
      # degree days cannot be negative
      ret[ret < 0] = 0
  
      prefix = 'CDD' if cooling else 'HDD'
      ret.name = '{}_{}'.format(prefix, base_temperature)
  
      return ret
docs: Calculates degree days, starting with a series of temperature equivalent values
  
      Parameters
      ----------
      temperature_equivalent : Pandas Series
      base_temperature : float
      cooling : bool
          Set True if you want cooling degree days instead of heating degree days
  
      Returns
      -------
      Pandas Series called HDD_base_temperature for heating degree days or
      CDD_base_temperature for cooling degree days.