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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 has_channel(val: Any) -> bool: """Returns whether the value has a channel representation. Returns: If `val` has a `_has_channel_` method and its result is not NotImplemented, that result is returned. Otherwise, if `val` has a `_has_mixture_` method and its result is not NotImplemented, that result is returned. Otherwise if `val` has a `_has_unitary_` method and its results is not NotImplemented, that result is returned. Otherwise, if the value has a _channel_ method return if that has a non-default value. Returns False if none of these functions exists. """

    channel_getter = getattr(val, '_has_channel_', None)
    result = NotImplemented if channel_getter is None else channel_getter()

    if result is not NotImplemented:
        return result

    result = has_mixture_channel(val)
    if result is not NotImplemented and result:
        return result

    # No has methods, use `_channel_` or delegates instead.
    return channel(val, None) is not None