element.position(x, y, [opt])Set the element position to x and y coordinates. This is almost equivalent to
element.set('position', { x: x, y: y }, opt). However, this method provides some additional functionality.
If you set opt.parentRelative flag to true, the x and y
coordinates will be treated relatively to the parent element of this element. If position() is called
without arguments, it returns the current position. If position({ parentRealtive: true }) is called
without x and y coordinates and with the parentRelativeflag set to true,
the method returns the current position of the element relative to its parent.