Classes and 'self'

Hello, I have been following a lecture on creating classes in Python and I tried to run the same code as in the solution to the exercise, but it did not want to work. So the code beings with: class BankAccount(object):     def _init_(self, balance = 0):     self.balance = balance <rest of the code> And when I try to run: my_bank = BankAccount(300) ===> BankAccount() takes no arguments.   Could someone help me with that? I am pretty sure I copied precisely the same code as in the ex. solutions...