class X: pass
class Y: pass
class A(X): pass 
class B(Y): pass 
class D(A, B): pass
print([cls.__name__ for cls in D.__mro__])

sum([10, 20, 30, 40], 10) - sum([], 10)

class C: pass
class D (C): __slots__ = ['a']
X = D() 
X.a = 1
class A: __slots__ = ['b']
class B (A): __slots__ = ['b']
Y = B() 
Y.b = 1
print(hasattr(X, '__dict__'), hasattr(Y, '__dict__'))

x = 9
y = 2
divmod(x, y) == (x // y, x % y), divmod(x, y) is (x // y, x % y)

class X: pass
class A(X): pass 
class B(X): pass 
class D(A, B): pass
print([cls.__name__ for cls in D.__mro__])

#задача
class A:
    count = 0
    def __init__(self):
        A.count = A.count + 1
    def get(self):
        return A.count
x, y, z = A(), A(), A()
print(x.get(), A().__class__.get(A()), z.__class__.get(y))

class A:
    count = 0 
    def __init__(self):
        A.count += 1
    def print_count():
        print(A.count)  
    print_count = staticmethod(print_count)
    
class B(A): pass

x, y, z = B(), A(), B() 
B.print_count()

class A:
    count = 0 
    def __init__(self) :
        self.__class__.count += 1
  
class B(A):
    pass
                  
class C(A):
    pass 

x, y, z = B(), A(), C()
print(A.count, B.count, C.count)

class A:
    count = 0
    @classmethod
    def inc(cls):
        cls.count += 1 
    def __init__ (self):
        self.inc() 
        
class B(A):
    count = 0
    def __init__(self): 
        A.__init__(self)
        
class C(A): 
    count = 0
    
x = A()  
y1, y2 = B(), B() 
z1, z2, z3 = C(), C(), C()
print(x.count, y1.count, z1.count)

import random
random.random() < random.randint(1, 10)