code: def PrependUOffsetTRelativeSlot(self, o, x, d):
          
  
          if x != d:
              self.PrependUOffsetTRelative(x)
              self.Slot(o)
docs: PrependUOffsetTRelativeSlot prepends an UOffsetT onto the object at
          vtable slot `o`. If value `x` equals default `d`, then the slot will
          be set to zero and no other data will be written.