To turn on assessment
        :param assessment: string

def on_assessment(self, assessment):
        """
        To turn on assessment
        :param assessment: string
        """

        assessmentObj = self.get_assessment(assessment)

        url = '/datastream/' + str(assessmentObj.get_datastream()) + '/on?assessment=' + str(assessment)
        response = self.http.post(url,"")
        return Schemas.Assessment(assessment=response[0])