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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 pept_diff(p1, p2):
 """ Return the number of differences betweeen 2 peptides :param str p1: Peptide 1 :param str p2: Peptide 2 :return: The number of differences between the pepetides :rtype: int 1 2 4 0 """

    if len(p1) != len(p2):
        return -1
    else:
        return sum([p1[i] != p2[i] for i in range(len(p1))])