parameters: (self)
docstring: Return a pre-order iterator for the tree.
docstring_summary: Return a pre-order iterator for the tree.
docstring_tokens: Return a pre - order iterator for the tree .
function: def pre_order(self):
          """Return a pre-order iterator for the tree."""
          yield self
          for child in self.children:
              for node in child.pre_order():
                  yield node
function_tokens: def pre_order ( self ) : yield self for child in self . children : for node in child . pre_order ( ) : yield node