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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def render_inner(self, token):
 """ Recursively renders child tokens. Joins the rendered strings with no space in between. If newlines / spaces are needed between tokens, add them in their respective templates, or override this function in the renderer subclass, so that whitespace won't seem to appear magically for anyone reading your program. Arguments: token: a branch node who has children attribute. """

        rendered = [self.render(child) for child in token.children]
        return ''.join(rendered)