def undefined_field(name, field, fields=None, value=None):
    value_str = " for '%s'" % value if value else ""
    result = ["'%s.%s' doesn't exist%s" % (name, field, value_str)]
    result.append((name, fields or "none") % "'%s' possible configurations are %s")
    return "\n".join(result)
dataset/ETHPy150Open conan-io/conan/conans/model/config_dict.py/undefined_field/swapped operands of `%`