Whats wrong with writing it like this?

Question

class X :
def __init__(self):
self.a = []
self.b = []
self.c = []

Should it instead be:

class X :
def __init__(self, a, b, c):
self.a = []
self.b = []
self.c = []

???

Answer 1

It won't work like this.
You should initialize a class first unless.

In your case, try

x = X()
x.a.append(something)

Answer 2

The first one takes no arguments when initialize an instance X while the second one needs a, b, c.
If not, the second one will raise errors. Which one to use depends on your practical situations.

Answer 3

Yuming Chen
In this case :

class X :
def __init__(self):
self.a = []
self.b = []
self.c = []

If i want to append to a, does X.a.append() work?