22/10/30 03:14:13.07 9F5gJDkR0.net
具体的にこれですが
class A :
L = []
def __init__(self): pass
class X :
L = []
def __init__(self): self.L = []
a = A()
a.L.append(7)
b = A()
print(b.L) # 新規生成なのに値が入ってる
a = X()
a.L.append(7)
b = X()
print(b.L) # 正常
print(a.L) # 正常