pickle with constant filesize

[Thomas Thiele]

Hallo!

I want to pickle different instances (with different datas) of a class
to a file.
But I how can I realize that every file has exact the same size (every
time when I pickle such a instance of a class)?
How can I calculate the size of the pickle file?

class Myclass:
    def __init__(self):
        self.a = 0
        self.b = 0
        self.c = []

...

x1 = Myclass()
x2 = Myclass()
x1.c = [1]
x2.c = [1,2,3,4,5]

Any Ideas?

Thanks Thomas