variable not defined inside a list comprehension

[Phidias618]

Hello, in a program i have a class like this one but when in run the code i get that x is not defined, is this problem relative to list comprehension?

class MyClass:
    x = 8
    y = 9
    grid = [[0 for _ in range(x)] for _ in range(y)]

Error:
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "<input>", line 4, in MyClass
  File "<input>", line 4, in <listcomp>
NameError: name 'x' is not defined