The optimization got moved to unicode objects during the great Python 3 upheaval and AFAIK still remains unimplemented for what are now bytes objects. The param

The optimization got moved to unicode objects during the great Python 3 upheaval and AFAIK still remains unimplemented for what are now bytes objects. The paramiko SSH library relied on it heavily, as a result its runtime is (AFAIK still) horrific on Python 3