from mapscript import mapObj,layerObj
wkt = '''GEOGCS["GCS_Chatham_Island_1971",DATUM["Chatham_Island_1971",SPHEROID["International_1924",6378388,297]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295],AUTHORITY["EPSG","37217"]]'''
m = mapObj('')
m.setWKTProjection(wkt)
lyr = layerObj(m)
lyr.setWKTProjection(wkt)