Take a look at the following example, which clearly explains the purpose of self
class Restaurant(object):
bankrupt = False
def open_branch(self):
if not self.bankrupt:
print("branch opened")
#create instance1
>>> x = Restaurant()
>>> x.bankrupt
False
#create instance2
>>> y = Restaurant()
>>> y.bankrupt = True
>>> y.bankrupt
True
>>> x.bankrupt
False
self
is used/needed to distinguish between instances.