Nurdok

>>> seq_x = [1, 2, 3, 4]
>>> seq_y = 'abc'
>>> [(x,y) for x in seq_x for y in seq_y]
1: [(1, 'a'),
 (1, 'b'),
 (1, 'c'),
 (2, 'a'),
 (2, 'b'),
 (2, 'c'),
 (3, 'a'),

Nurdok

class SingletonType(type):

    def __call__(cls, *args, **kwargs):
        try:
            return cls.__instance
        except AttributeError:
            cls.__instance = super(SingletonType, cls).__call__(*args, **kwargs)
            return cls.__instance