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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 dePeriod(arr):
 """make an array of periodic angles increase linearly"""

    diff= arr-nu.roll(arr,1,axis=1)
    w= diff < -6.
    addto= nu.cumsum(w.astype(int),axis=1)
    return arr+_TWOPI*addto