rb_define_alias(notmuch_rb_cMessage, "<<", "add_tag");
rb_define_method(notmuch_rb_cMessage, "remove_tag", notmuch_rb_message_remove_tag, 1);
rb_define_method(notmuch_rb_cMessage, "remove_all_tags", notmuch_rb_message_remove_all_tags, 0);
rb_define_alias(notmuch_rb_cMessage, "<<", "add_tag");
rb_define_method(notmuch_rb_cMessage, "remove_tag", notmuch_rb_message_remove_tag, 1);
rb_define_method(notmuch_rb_cMessage, "remove_all_tags", notmuch_rb_message_remove_all_tags, 0);