def is_group(item_type):
    """Return whether or not the given item_type is a group."""
    group_types = [
        'adversary',
        'campaign',
        'document',
        'email',
        'event',
        'incident',
        'intrusion set',
        'signature',
        'report',
        'threat',
        'task'
    ]
    return item_type in group_types