docs: private static ExpressionTree getNullCheckedExpression(ExpressionTree condition) {
      condition = stripParentheses(condition);
      if (!(condition instanceof BinaryTree)) {
        return null;
      }
      BinaryTree bin = (BinaryTree) condition;
      ExpressionTree other;
      if (bin.getLeftOperand().getKind() == Kind.NULL_LITERAL) {
        other = bin.getRightOperand();
      } else if (bin.getRightOperand().getKind() == Kind.NULL_LITERAL) {
        other = bin.getLeftOperand();
      } else {
        return null;
      }
      return other;
    }