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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 has_started(self):
 """Tests if this assessment has begun. return: (boolean) - ``true`` if the assessment has begun, ``false`` otherwise *compliance: mandatory -- This method must be implemented.* """

        assessment_offered = self.get_assessment_offered()
        if assessment_offered.has_start_time():
            return DateTime.utcnow() >= assessment_offered.get_start_time()
        else:
            return True