def __getitem__(self, key):
values = [value for (k, value) in self._internal if k == key]<EOL>if not values:<EOL><INDENT>raise KeyError(key)<EOL><DEDENT>else:<EOL><INDENT>return values<EOL><DEDENT>
A list of values for the key.

        This is a copy, so comment['title'].append('a title') will not
        work.