'Returns true if item is has a given tag.'

def item_has_tag(self, user, item, tag):

    if isinstance(tag, string_types):
        tag_name = tag
    elif isinstance(tag, galaxy.model.Tag):
        tag_name = tag.name
    item_tag_assoc = self._get_item_tag_assoc(user, item, tag_name)
    if item_tag_assoc:
        return True
    return False
