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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 is_indel(reference_bases, alternate_bases):
 """ Return whether or not the variant is an INDEL """

    if len(reference_bases) > 1:
        return True
    for alt in alternate_bases:
        if alt is None:
            return True
        elif len(alt) != len(reference_bases):
            return True
    return False