fix: remove mutable object as default for method/function values use immutable tuples as default value markers for parameters where a None value is valid. It does seem that the _marker objects are used in places where None would not be considered a valid value.

#!/usr/bin/env python
from __future__ import print_function
import zlib, base64, sys
print(base64.encodestring(zlib.compress(sys.stdin.read())))