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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 on_session_created(self, session_context):
        ''' Invoked to execute code when a new session is created.

        This method calls ``on_session_created`` on each handler, in order,
        with the session context passed as the only argument.

        May return a ``Future`` which will delay session creation until the
        ``Future`` completes.

        '''
        for h in self._handlers:
            result = h.on_session_created(session_context)
            yield yield_for_all_futures(result)
        raise gen.Return(None)