def METHOD_NAME(self, space):
    typ = Type(self)
    if typ == 'Object':
        return self
    elif typ == 'Boolean':  # Unsure ... todo check here
        return space.Boolean.create((self, ), space)
    elif typ == 'Number':  # ?
        return space.Number.create((self, ), space)
    elif typ == 'String':  # ?
        return space.String.create((self, ), space)
    elif typ == 'Null' or typ == 'Undefined':
        raise MakeError('TypeError',
                        'undefined or null can\'t be converted to object')
    else:
        raise RuntimeError()