<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def GetPupil(self):
 """Retrieve pupil data """

    pupil_data = _co.namedtuple('pupil_data', ['ZemaxApertureType',
                                               'ApertureValue',
                                               'entrancePupilDiameter',
                                               'entrancePupilPosition',
                                               'exitPupilDiameter',
                                               'exitPupilPosition',
                                               'ApodizationType',
                                               'ApodizationFactor'])
    data = self._ilensdataeditor.GetPupil()
    return pupil_data(*data)