def __delattr__(self, key, force=False):
if self._valid_name(key):<EOL><INDENT>del self[key]<EOL><DEDENT>elif getattr(self, '<STR_LIT>', True):<EOL><INDENT>super(MutableAttr, self).__delattr__(key)<EOL><DEDENT>else:<EOL><INDENT>raise TypeError(<EOL>"<STR_LIT>".format(<EOL>cls=self.__class__.__name__<EOL>)<EOL>)<EOL><DEDENT>
Delete an attribute.

key: The name of the attribute