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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 rebin2x2(a):
 """ Wrapper around rebin that actually rebins 2 by 2 """

    inshape = np.array(a.shape)
    if not (inshape % 2 == np.zeros(2)).all(): # Modulo check to see if size is even
        raise RuntimeError, "I want even image shapes !"
        
    return rebin(a, inshape/2)