What unit of time does the delay refer to?

Question

In the tracer(x,y) function of python's standard turtle graphics where x is said to be the number of updates and y is said to be the delay time and calling the tracer does turn of the tracing animation. For example, in the call of turtle.tracer(1, 50), what unit of time does the delay of 50 refer to?

Answer 1

According to the docs:

Set or return the drawing delay in milliseconds. (This is approximately the time interval between two consecutive canvas updates.) The longer the drawing delay, the slower the animation.