On Jan 10, 12:36 pm, "zsl... at gmail.com" <levili... at gmail.com> wrote: > I've figured it out, it is default argument. > print y() > gives 13 as result. > > It's a bit evil though. Why? It's the same syntax as with functions: x=3 def y(x=x): return x+10 print y(2) # prints 12 print y() # prints 13