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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 knuth_sum(a, b):
 """Error-free transformation of the sum of two floating point numbers according to D.E. Knuth. The Art of Computer Programming: Seminumerical Algorithms, volume 2. Addison Wesley, Reading, Massachusetts, second edition, 1981. The underlying problem is that the exact sum a+b of two floating point number a and b is not necessarily a floating point number; for example if you add a very large and a very small number. It is however known that the difference between the best floating point approximation of a+b and the exact a+b is again a floating point number. This routine returns the sum and the error. Algorithm 3.1 in <https://doi.org/10.1137/030601818>. """

    x = a + b
    z = x - a
    y = (a - (x - z)) + (b - z)
    return x, y