def reverse_field_path(model, path):
    """ Create a reversed field path.

    E.g. Given (Order, "user__groups"),
    return (Group, "user__order").

    Final field must be a related model, not a data field.

    """
    reversed_path = []
    parent = model
    pieces = path.split(LOOKUP_SEP)
    for piece in pieces:
        field = parent._meta.get_field(piece)
        direct = not field.auto_created or field.concrete
        # skip trailing data field if extant:
        if len(reversed_path) == 1 - len(pieces):  # final iteration
            try:
                get_model_from_relation(field)
            except NotRelationField:
                break
        if direct:
            related_name = field.related_query_name()
            parent = field.rel.to
        else:
            related_name = field.field.name
            parent = field.model
        reversed_path.insert(0, related_name)
    return (parent, LOOKUP_SEP.join(reversed_path))
dataset/ETHPy150Open sshwsfc/xadmin/xadmin/util.py/reverse_field_path/swapped operands of `-`