private static boolean operandIsKnown(@Nullable PyExpression operand, @NotNull TypeEvalContext context) {
    if (operand == null) return false;

    final PyType operandType = context.getType(operand);
    if (operandType instanceof PyStructuralType || PyTypeChecker.isUnknown(operandType, context)) return false;

    return true;
  }
private static boolean operandIsKnown(@Nullable PyExpression operand, @NotNull TypeEvalContext context)