parameters: (self, visitor = None)
docstring: The visitor, if given, must adhere to API of
          ITopicTreeVisitor. The visitor can be changed or
          set via setVisitor(visitor) before calling traverse().
docstring_summary: The visitor, if given, must adhere to API of
          ITopicTreeVisitor. The visitor can be changed or
          set via setVisitor(visitor) before calling traverse().
docstring_tokens: The visitor if given must adhere to API of ITopicTreeVisitor . The visitor can be changed or set via setVisitor ( visitor ) before calling traverse () .
function: def __init__(self, visitor = None):
          """The visitor, if given, must adhere to API of
          ITopicTreeVisitor. The visitor can be changed or
          set via setVisitor(visitor) before calling traverse()."""
          self.__handler = visitor
function_tokens: def __init__ ( self , visitor = None ) : self . __handler = visitor