import bpy  
  
class MoveBlackPawn(bpy.types.Operator):  
    bl_idname = "object.moveblackpawn_operator"  
    bl_label = "Move Black Pawn"  
  
    def execute(self, context):  
        context.active_object.location.y -= 2.75  
        return {'FINISHED'}  
  
def register():  
    bpy.utils.register_class(MoveBlackPawn)  
  
if __name__ == "__main__":  
    register()