def get_metadata(self, entity_type, entity_id):
if not is_valid_uuid(entity_id):<EOL><INDENT>raise StorageArgumentException(<EOL>'<STR_LIT>'.format(entity_id))<EOL><DEDENT>return self._authenticated_request.to_endpoint('<STR_LIT>'.format(entity_type, entity_id)).return_body().get()<EOL>
Get metadata of an entity.

        Args:
            entity_type (str): Type of the entity. Admitted values: ['project',
                'folder', 'file'].
            entity_id (str): The UUID of the entity to be modified.

        Returns:
            A dictionary of the metadata::

                {
                    u'bar': u'200',
                    u'foo': u'100'
                }

        Raises:
            StorageArgumentException: Invalid arguments
            StorageForbiddenException: Server response code 403
            StorageNotFoundException: Server response code 404
            StorageException: other 400-600 error codes