def conj_schema(conj: dict) -> str:
    """
    create a field list that used by filter to save in the scheme keys
    for example: ModelA.objects.filter(x=1, y=2) -> return "x,y"

    the conj object contain field:value pair used by filter function
    """
    field_list = conj.keys() if conj else []
    parts = [str(field) for field in field_list]

    return ','.join(parts)