[mark@toy ~/PP2ndEd/dev/examples/Part3/Mixed/Regist]$ python register.py

Test1:
callback1 => spam number 0
callback1 => spam number 1
callback1 => spam number 2

Test2:
callback2 => spamspamspam
callback2 => spamspamspamspam
callback2 => spamspamspamspamspam