docs: def f_cell_temp(poa_global, wind_speed, air_temp):
      """
      Calculate cell temperature.
  
      :param poa_global: plane of array global irradiance [W/m**2]
      :param wind_speed: wind speed [m/s]
      :param air_temp: ambient dry bulb air temperature [degC]
      :return: cell temperature [degC]
      """
      temps = pvlib.pvsystem.sapm_celltemp(poa_global, wind_speed, air_temp)
      return temps['temp_cell'].values, temps['temp_module'].values