def __setattr__(self, attr, val):
        try :
            #print "Transform.__setattr__", attr, val
            # Functions through normal inheritance
            return DependNode.__setattr__(self,attr,val)
        except AttributeError, e:
            # Functions via shape inheritance , and then, implicitly, Attributes
            #print "Trying shape"
            shape = self.getShape()
            if shape:
                try:
                    return setattr(shape,attr, val)
                except AttributeError: pass
            raise e
Checks in the following order:
dataset/ETHPy150Open CountZer0/PipelineConstructionSet/python/maya/site-packages/pymel-1.0.3/pymel/core/nodetypes.py/Transform.__setattr__