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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 childFactory(self, ctx, name):
 """ Return a shell page wrapped around the Item model described by the webID, or return None if no such item can be found. """

        try:
            o = self.webapp.fromWebID(name)
        except _WebIDFormatException:
            return None
        if o is None:
            return None
        return self.webViewer.wrapModel(o)