#vulnerable code 
                              public ForStatement forStatement(AstNode astNode) {
    AstNode forStatementNode = astNode;
    Token asyncToken = null;
    if (astNode.is(PythonGrammar.ASYNC_STMT)) {
      asyncToken = toPyToken(astNode.getFirstChild().getToken());
      forStatementNode = astNode.getFirstChild(PythonGrammar.FOR_STMT);
    }
    Token forKeyword = toPyToken(forStatementNode.getFirstChild(PythonKeyword.FOR).getToken());
    Token inKeyword = toPyToken(forStatementNode.getFirstChild(PythonKeyword.IN).getToken());
    Token colon = toPyToken(forStatementNode.getFirstChild(PythonPunctuator.COLON).getToken());
    List<Expression> expressions = expressionsFromExprList(forStatementNode.getFirstChild(PythonGrammar.EXPRLIST));
    List<Expression> testExpressions = expressionsFromTest(forStatementNode.getFirstChild(PythonGrammar.TESTLIST));
    AstNode firstSuite = forStatementNode.getFirstChild(PythonGrammar.SUITE);
    Token firstIndent = firstSuite.getFirstChild(PythonTokenType.INDENT) == null ? null : toPyToken(firstSuite.getFirstChild(PythonTokenType.INDENT).getToken());
    Token firstNewLine = firstSuite.getFirstChild(PythonTokenType.INDENT) == null ? null : toPyToken(firstSuite.getFirstChild(PythonTokenType.NEWLINE).getToken());
    Token firstDedent = firstSuite.getFirstChild(PythonTokenType.DEDENT) == null ? null : toPyToken(firstSuite.getFirstChild(PythonTokenType.DEDENT).getToken());
    StatementList body = getStatementListFromSuite(firstSuite);
    AstNode lastSuite = forStatementNode.getLastChild(PythonGrammar.SUITE);
    Token lastIndent = lastSuite.getFirstChild(PythonTokenType.INDENT) == null ? null : toPyToken(lastSuite.getFirstChild(PythonTokenType.INDENT).getToken());
    Token lastNewLine = lastSuite.getFirstChild(PythonTokenType.INDENT) == null ? null : toPyToken(lastSuite.getFirstChild(PythonTokenType.NEWLINE).getToken());
    Token lastDedent = lastSuite.getFirstChild(PythonTokenType.DEDENT) == null ? null : toPyToken(lastSuite.getFirstChild(PythonTokenType.DEDENT).getToken());
    AstNode elseKeywordNode = forStatementNode.getFirstChild(PythonKeyword.ELSE);
    Token elseKeyword = null;
    Token elseColonKeyword = null;
    if (elseKeywordNode != null) {
      elseKeyword = toPyToken(elseKeywordNode.getToken());
      elseColonKeyword = toPyToken(elseKeywordNode.getNextSibling().getToken());
    }
    StatementList elseBody = lastSuite == firstSuite ? null : getStatementListFromSuite(lastSuite);
    return new ForStatementImpl(forStatementNode, forKeyword, expressions, inKeyword, testExpressions, colon, firstNewLine, firstIndent,
      body, firstDedent, elseKeyword, elseColonKeyword, lastNewLine, lastIndent, elseBody, lastDedent, asyncToken);
  } 
                            #location 19 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              public ForStatement forStatement(AstNode astNode) {
    AstNode forStatementNode = astNode;
    Token asyncToken = null;
    if (astNode.is(PythonGrammar.ASYNC_STMT)) {
      asyncToken = toPyToken(astNode.getFirstChild().getToken());
      forStatementNode = astNode.getFirstChild(PythonGrammar.FOR_STMT);
    }
    Token forKeyword = toPyToken(forStatementNode.getFirstChild(PythonKeyword.FOR).getToken());
    Token inKeyword = toPyToken(forStatementNode.getFirstChild(PythonKeyword.IN).getToken());
    Token colon = toPyToken(forStatementNode.getFirstChild(PythonPunctuator.COLON).getToken());
    List<Expression> expressions = expressionsFromExprList(forStatementNode.getFirstChild(PythonGrammar.EXPRLIST));
    List<Expression> testExpressions = expressionsFromTest(forStatementNode.getFirstChild(PythonGrammar.TESTLIST));
    AstNode firstSuite = forStatementNode.getFirstChild(PythonGrammar.SUITE);
    StatementList body = getStatementListFromSuite(firstSuite);
    AstNode lastSuite = forStatementNode.getLastChild(PythonGrammar.SUITE);
    AstNode elseKeywordNode = forStatementNode.getFirstChild(PythonKeyword.ELSE);
    Token elseKeyword = null;
    Token elseColonKeyword = null;
    if (elseKeywordNode != null) {
      elseKeyword = toPyToken(elseKeywordNode.getToken());
      elseColonKeyword = toPyToken(elseKeywordNode.getNextSibling().getToken());
    }
    Token lastIndent = firstSuite == lastSuite ? null : suiteIndent(lastSuite);
    Token lastNewLine = firstSuite == lastSuite ? null : suiteNewLine(lastSuite);
    Token lastDedent = firstSuite == lastSuite ? null : suiteDedent(lastSuite);
    StatementList elseBody = firstSuite == lastSuite ? null : getStatementListFromSuite(lastSuite);
    return new ForStatementImpl(forStatementNode, forKeyword, expressions, inKeyword, testExpressions, colon, suiteNewLine(firstSuite), suiteIndent(firstSuite),
      body, suiteDedent(firstSuite), elseKeyword, elseColonKeyword, lastNewLine, lastIndent, elseBody, lastDedent, asyncToken);
  }