class namespace scope

class_scope.py

a = 'global'

class Fred:
    a = 'class'
    b = (a for i in range(10))
    c = [a for i in range(10)]
    d = a
    e = lambda: a
    f = lambda a=a: a
    
    @staticmethod
    def g():
        return a

print(Fred.a)  # class
print(next(Fred.b))  # global
print(Fred.c[0])  # class in Python 2, global in Python 3
print(Fred.d)  # class
print(Fred.e())  # global
print(Fred.f())  # class
print(Fred.g())  # global

A comprehensive explanation: http://stackoverflow.com/questions/13905741/accessing-class-variables-from-a-list-comprehension-in-the-class-definition/13913933#13913933