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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 install_twisted():
 """ If twisted is available, make `emit' return a DeferredList This has been successfully tested with Twisted 14.0 and later. """

    global emit, _call_partial
    try:
        from twisted.internet import defer
        emit = _emit_twisted
        _call_partial = defer.maybeDeferred
        return True
    except ImportError:
        _call_partial = lambda fn, *a, **kw: fn(*a, **kw)
        return False