def make_plus_fields(obj):
    """
    Add a '+' to the key of non-standard fields.

    dispatch to recursive _make_plus_helper based on _type field
    """
    fields = standard_fields.get(obj['_type'], dict())
    return _make_plus_helper(obj, fields)
Add a '+' to the key of non-standard fields.

    dispatch to recursive _make_plus_helper based on _type field