public static @Nullable PsiExpression findNullCheckedOperand(PsiExpression expression) {
    if (!(expression instanceof PsiBinaryExpression binaryExpression)) return null;
    if (!JavaTokenType.EQEQ.equals(binaryExpression.getOperationTokenType())) return null;
    if (ExpressionUtils.isNullLiteral(binaryExpression.getLOperand())) {
      return binaryExpression.getROperand();
    }
    else if (ExpressionUtils.isNullLiteral(binaryExpression.getROperand())) {
      return binaryExpression.getLOperand();
    }
    else {
      return null;
    }
  }
public static @Nullable PsiExpression findNullCheckedOperand(PsiExpression expression)