code: def set_mask_from_shapefile(self, shapefile_path, cell_size):
          
          # make sure paths are absolute as the working directory changes
          shapefile_path = os.path.abspath(shapefile_path)
          # ADD MASK
          with tmp_chdir(self.project_directory):
              mask_name = '{0}.msk'.format(self.project_manager.name)
              msk_file = WatershedMaskFile(project_file=self.project_manager,
                                           session=self.db_session)
  
              msk_file.generateFromWatershedShapefile(shapefile_path,
                                                      cell_size=cell_size,
                                                      out_raster_path=mask_name,
                                                      load_raster_to_db=self.load_rasters_to_db)
docs: Adds a mask from a shapefile