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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 get_simple_date(datestring):
 """Transforms a datestring into shorter date 7.9.2017 > 07.09 Expects the datestring to be format 07.09.2017. If this is not the case, returns string "Failed". Keyword arguments: datestring -- a string Returns: String -- The date in format "dd.MM." or "Failed" """

    simple_date = re.compile(r"\d{1,2}(\.)\d{1,2}")
    date = simple_date.search(datestring)
    if date:
        dates = date.group().split(".")
        if len(dates[0]) == 1:
            dates[0] = add_zero(dates[0])
        if len(dates[1]) == 1:
            dates[1] = add_zero(dates[1])

        if date_is_valid(dates):
            return '.'.join(dates) + '.'
        return "Failed"