human
Solve the following python programming problem given the following code:
def _visitPattern(self, tree, pattern, visitor) : 
    '
        For all subtrees that match the pattern, execute the visit action.
        ' 
    tokenizer = TreePatternLexer (rootTokenType) 
    parser = TreePatternParser (tokenizer, self, TreePatternTreeAdaptor ()) 
    tpattern = parser.pattern () 
    if ((tpattern is None) or tpattern.isNil () or isinstance (tpattern, WildcardTreePattern)) : 
        return 
rootTokenType = tpattern.getType () 
    def rootvisitor(tree, parent, childIndex, labels) : 
        labels = { 
            
} 
        if self._parse (tree, tpattern, labels) : 
            visitor (tree, parent, childIndex, labels) 
self.visit (tree, rootTokenType, rootvisitor) 

    
    

    Fix the buggy line: tokenizer = TreePatternLexer (rootTokenType)
assistant
#Here is Python code to fix the buggy line: tokenizer = TreePatternLexer (rootTokenType)
.

tokenizer = TreePatternLexer (pattern)