On Tue, Apr 23, 2019 at 08:27:15PM +0530, Arup Rakshit wrote: > >You probably want: > > > > def __init__(self, list=None): > > if list is None: > > list =  > > self.list = list > > That is really a new thing to me. I didn't know. Why list=None in the > parameter list is different than in the body of __init__ method? Can you > elaborate this?
Try running this code and see what happens: def make_default(): print("creating a new list") return  def function(arg=make_default()): arg.append(1) return arg Now call: function() function() function() and see if you can work out what is happening. Hint: how many new lists are created? when are they created? -- Steven _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor