code: def cloud_cover_to_ghi_linear(self, cloud_cover, ghi_clear, offset=35,
                                    **kwargs):
          
  
          offset = offset / 100.
          cloud_cover = cloud_cover / 100.
          ghi = (offset + (1 - offset) * (1 - cloud_cover)) * ghi_clear
          return ghi
docs: Convert cloud cover to GHI using a linear relationship.
  
          0% cloud cover returns ghi_clear.
  
          100% cloud cover returns offset*ghi_clear.
  
          Parameters
          ----------
          cloud_cover: numeric
              Cloud cover in %.
          ghi_clear: numeric
              GHI under clear sky conditions.
          offset: numeric, default 35
              Determines the minimum GHI.
          kwargs
              Not used.
  
          Returns
          -------
          ghi: numeric
              Estimated GHI.
  
          References
          ----------
          Larson et. al. "Day-ahead forecasting of solar power output from
          photovoltaic plants in the American Southwest" Renewable Energy
          91, 11-20 (2016).