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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 mixture( val: Any, default: Any = RaiseTypeErrorIfNotProvided) -> Sequence[Tuple[float, Any]]: """Return a sequence of tuples representing a probabilistic combination. A mixture is described by an iterable of tuples of the form (probability of object, object) The probability components of the tuples must sum to 1.0 and be between 0 and 1 (inclusive). Args: val: The value whose mixture is being computed. default: A default value if val does not support mixture. Returns: An iterable of tuples of size 2. The first element of the tuple is a probability (between 0 and 1) and the second is the object that occurs with that probability in the mixture. The probabilities will sum to 1.0. """


    getter = getattr(val, '_mixture_', None)
    result = NotImplemented if getter is None else getter()

    if result is not NotImplemented:
        return result
    if default is not RaiseTypeErrorIfNotProvided:
        return default

    if getter is None:
        raise TypeError(
            "object of type '{}' has no _mixture_ method.".format(type(val)))

    raise TypeError("object of type '{}' does have a _mixture_ method, "
                    "but it returned NotImplemented.".format(type(val)))