def full_parent_name(self):
        """Retrieves the fully qualified parent command name.

        This the base command name required to execute it. For example,
        in ``?one two three`` the parent name would be ``one two``.
        """
        entries = []
        command = self
        while command.parent is not None:
            command = command.parent
            entries.append(command.name)

        return ' '.join(reversed(entries))