code: def get_area_def(self, dsid):
          
          if self.pps:
              # PPS:
              raise NotImplementedError
  
          if dsid.name.endswith('_pal'):
              raise NotImplementedError
  
          proj_str, area_extent = self._get_projection()
  
          nlines, ncols = self.nc[dsid.name].shape
  
          area = get_area_def('some_area_name',
                              "On-the-fly area",
                              'geosmsg',
                              proj_str,
                              ncols,
                              nlines,
                              area_extent)
  
          return area
docs: Get the area definition of the datasets in the file.
  
          Only applicable for MSG products!