from mapscript import mapObj,layerObj
wkt = '''PROJCS["WGS_1984_Web_Mercator",GEOGCS["GCS_WGS_1984_Major_Auxiliary_Sphere",DATUM["WGS_1984_Major_Auxiliary_Sphere",SPHEROID["WGS_1984_Major_Auxiliary_Sphere",6378137.0,0.0]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Mercator_1SP"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",0.0],PARAMETER["latitude_of_origin",0.0],UNIT["Meter",1.0]]'''
m = mapObj('')
m.setWKTProjection(wkt)
lyr = layerObj(m)
lyr.setWKTProjection(wkt)