code: def _moveBy(self, value, **kwargs):
          
          x, y = value
          t = transform.Offset(x, y)
          self.transformBy(tuple(t), **kwargs)
docs: This is the environment implementation of
          :meth:`BaseObject.moveBy`.
  
          **value** will be an iterable containing two
          :ref:`type-int-float` values defining the x and y
          values to move the object by. It will have been
          normalized with :func:`normalizers.normalizeTransformationOffset`.
  
          Subclasses may override this method.