@abc.abstractmethod<EOL><INDENT>def set_spatial_unit(self, spatial_unit):<DEDENT>
pass<EOL>
Sets the spatial unit.

        :param spatial_unit: the new spatial unit
        :type spatial_unit: ``osid.mapping.SpatialUnit``
        :raise: ``InvalidArgument`` -- ``spatial_unit`` is invalid
        :raise: ``NoAccess`` -- ``Metadata.isReadOnly()`` is ``true``
        :raise: ``NullArgument`` -- ``spatial_unit`` is ``null``
        :raise: ``Unsupported`` -- ``spatial_unit`` type is not supported

        *compliance: mandatory -- This method must be implemented.*