def postinit(self, items=None, body=None, type_annotation=None):
self.items = items<EOL>self.body = body<EOL>self.type_annotation = type_annotation<EOL>
Do some setup after initialisation.

        :param items: The pairs of context managers and the names
            they are assigned to.
        :type items: list(tuple(NodeNG, AssignName or None)) or None

        :param body: The contents of the ``with`` block.
        :type body: list(NodeNG) or None