'Copy tags from `source_hda` to this HDA and assign them the user `target_user`.'

def copy_tags_from(self, target_user, source_hda):

    for source_tag_assoc in source_hda.tags:
        new_tag_assoc = source_tag_assoc.copy()
        new_tag_assoc.user = target_user
        self.tags.append(new_tag_assoc)
