'Adds a cohort by name, returning its ID.'

def add_manual_cohort(self, course_fixture, cohort_name):

    url = (((LMS_BASE_URL + '/courses/') + course_fixture._course_key) + '/cohorts/')
    data = json.dumps({'name': cohort_name, 'assignment_type': 'manual'})
    response = course_fixture.session.post(url, data=data, headers=course_fixture.headers)
    self.assertTrue(response.ok, 'Failed    to    create    cohort')
    return response.json()['id']
