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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 _check_if_ins_is_dup(self, start, insertion):
 """Helper to identify an insertion as a duplicate :param start: 1-based insertion start :type start: int :param insertion: sequence :type insertion: str :return (is duplicate, variant start) :rtype (bool, int) """

        is_dup = False    # assume no
        variant_start = None

        dup_candidate_start = start - len(insertion) - 1
        dup_candidate = self._ref_seq[dup_candidate_start:dup_candidate_start + len(insertion)]
        if insertion == dup_candidate:
            is_dup = True
            variant_start = dup_candidate_start + 1

        return is_dup, variant_start