How to debug OOP Class/Method in Python -

i'm attempting canonical pedagogical programming exercise of building program simulate card game. how far am:

 class card:       def __init__(self, suit, rank):          self.suit = suit          self.rank = rank          self.card = str(self.suit) + " " + str(self.rank)   class deck:       def __init__(self):          self.deck = []       def deck_maker(self):          ranks = range(1, 11) + ["j", "q", "k", "a"]          suits = ["club", "heart", "spade", "diamond"]           return self.deck.append(card(suits[0], ranks[0])) 

obviously i'm not done, have loop on suits , ranks construct deck. however, before continuing want check i'm on track. want print results after invoking deck_maker method. have attempted below code...

 def __str__(self):          d = self.deck          d2 = d.deck_maker()          return str(d2) 

unfortunately, print(deck().deck_maker()) returns none.

what doing wrong? more generally, how programmers poke around within classes , methods while make them?

thanks!

the append method on list returns none expected. try splitting lines:

deck = deck() deck.deck_maker() print(deck) 

or change method deck_maker be:

def deck_maker(self):     ranks = range(1, 11) + ["j", "q", "k", "a"]     suits = ["club", "heart", "spade", "diamond"]     self.deck.append(card(suits[0], ranks[0]))     return self 

edit: there problem in str method. when set d self.deck setting list. list doesn't know method deck_maker. try changing method below. turn list string. make more readable, want add str method card class.

def __str__(self):     return str(self.deck)