parameters: (self, tree)
docstring: Creates a TreeWalker
  
          :arg tree: the tree to walk
docstring_summary: Creates a TreeWalker
docstring_tokens: Creates a TreeWalker
function: def __init__(self, tree):
          """Creates a TreeWalker
  
          :arg tree: the tree to walk
  
          """
          self.tree = tree
function_tokens: def __init__ ( self , tree ) : self . tree = tree