code: def crs(self, crs):
          
          if isinstance(crs, QgsCoordinateReferenceSystem):
              self._crs = crs
              self._is_ready = False
          else:
              raise InvalidExtentError('%s is not a valid CRS object.' % crs)
docs: Setter for extent_crs property.
  
          :param crs: The coordinate reference system for the analysis boundary.
          :type crs: QgsCoordinateReferenceSystem