无法在类中使用def __str__打印实例？

我正在学习Python,目前正在学习Classes.我无法打印类的实例,代码如下.

class CreditCard:
""" This is properly intended, but CNTRL+K resulted in unindentation
     (stackoverflow's cntrl+k)"""


def __init__(self,customer,bank,account,limit):
    """ Initializing the variables inside the class
        Setting the Initial Balance as Zero
        Customer : Name of the Customer
        bank : Name of the Bank
        balance : will be zero, initial
        account : accoount number or identifier, generally a string
        limit : account limit/ credit limit
    """
    self.customer = customer
    self.bank = bank
    self.accnt=account
    self.limit = limit
    self.balance = 0

def get_customer(self):
    """ returns the name of the customer """
    return self.customer

def get_bank(self):
    """ returns the Bank name """
    return self.bank

def get_account(self):
    """ returns the Account Number """
    return self.account

def get_limit(self):
    """ returns the Credit Limit """
    return self.limit

def get_balance(self):
    """ returns the Balance """
    return self.balance

def charge(self,price):
    """ swipe charges on card, if sufficient credit limit
        returns True if  transaction is processed, False if
        declined """
    if price + self.balance > self.limit:
        return False
    else:
        self.balance=price+self.balance
        # abve can be written as
        # self.balance+=price
        return True
    def make_payment(self,amount):
        """ cust pays money to bank, that reduces balance """
        self.balance = amount-self.balance
        # self.balance-=amount

    def __str__(self):
        """ string representation of Values """
        return self.customer,self.bank,self.account,self.limit

我没有错误地运行它.我创建了一个实例,

 cc=CreditCard('Hakamoora','Duesche',12345678910,5000)

这就是我所得到的.

    >>> cc
      <__main__.CreditCard instance at 0x0000000002E427C8>

应该包括什么来使它打印实例,比如

>>cc=CreditCard('Hakamoora','Duesche',12345678910,5000)
>>cc
>>('Hakamoora','Duesche',12345678910,5000)

请使用较少的技术术语(新手在这里)

pastebinlink:https://paste.ee/p/rD91N

也试过这些,

        def __str__(self):
            """ string representation of Values """
            return "%s,%s,%d,%d"%(self.customer,self.bank,self.account,self.limit)

和

           def __str__(self):
                """ string representation of Values """
                return "({0},{1},{2},{3})".format(self.customer,self.bank,self.account,self.limit)

谢谢,
6er

你混淆__str__和__repr__.考虑以下课程:

class Test(object):
    def __str__(self):
        return '__str__'

    def __repr__(self):
        return '__repr__'

你可以看到在哪里调用哪个方法:

>>> t = Test()
>>> t
__repr__
>>> print(t)
__str__
>>> [1, 2, t]
[1, 2, __repr__]
>>> str(t)
'__str__'
>>> repr(t)
'__repr__'

另外,请确保这两个方法都返回字符串.你现在正在返回一个元组,这会导致出现这样的错误:

TypeError: __str__ returned non-string (type tuple)