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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 map_age(age):
 """ Map age to correct age-group. """


        if age in [None, '']:
            return issuers.AgeGroup.UNKNOWN
        elif age == 'teens':
            return issuers.AgeGroup.YOUTH
        elif age in ['sixties', 'seventies', 'eighties', 'nineties']:
            return issuers.AgeGroup.SENIOR
        else:
            return issuers.AgeGroup.ADULT