parameters: (self, tree, filename)
docstring: Some fixers need to maintain tree-wide state.
          This method is called once, at the start of tree fix-up.
  
          tree - the root node of the tree to be processed.
          filename - the name of the file the tree came from.
docstring_summary: Some fixers need to maintain tree-wide state.
          This method is called once, at the start of tree fix-up.
docstring_tokens: Some fixers need to maintain tree - wide state . This method is called once at the start of tree fix - up .
function: def start_tree(self, tree, filename):
          """Some fixers need to maintain tree-wide state.
          This method is called once, at the start of tree fix-up.
  
          tree - the root node of the tree to be processed.
          filename - the name of the file the tree came from.
          """
          self.used_names = tree.used_names
          self.set_filename(filename)
          self.numbers = itertools.count(1)
          self.first_log = True
function_tokens: def start_tree ( self , tree , filename ) : self . used_names = tree . used_names self . set_filename ( filename ) self . numbers = itertools . count ( 1 ) self . first_log = True