Prompt not found by pexpect in python 3 environment

[beleki]

case 1:

TypeError: write() argument must be str, not bytes
when
spawn SshShell, terminal has outgoing and incoming logfiles defined

reason:
InteractiveSession spawn does not open logfile_send and logfile_read in binary mode

case 2:
prompt not found
when
push KeyauthenticatedShell
reason:
initial_prompt is defined as string