The pixelMove command moves objects by what appears as pixel units based on the current view. It takes two integer arguments which specify the direction in screen space an object should appear to move. The vector between the center pixel of the view and the specified offset is mapped to some world space vector which defines the relative amount to move the selected objects. The mapping is dependent upon the view.
Derived from mel command maya.cmds.pixelMove
import pymel.core as pm # move selected objects to the right (in current view) by one "pixel" pm.pixelMove( 1, 0 ) # move selected objects up by one "pixel" pm.pixelMove( 0, 1 )