[Twisted-Python] how to run ckeygen

I did "pip install twisted" and it seemed to install okay. Now I'm trying to get https://twistedmatrix.com/documents/current/_downloads/9620a18fe21cabe0de79c... running locally. To do so it says I need to first do "ckeygen -t rsa -f ssh-keys/ssh_host_rsa_key". ssh-keygen is a command that's commonly available on Linux systems but ckeygen... that appears to be a twisted thing. When I try to run that on Ubuntu I get a "-bash: ckeygen: command not found" error. Maybe there's a ckeygen.py file that I need to be running but if so idk where it is. Maybe if I did I could rename it to ckeygen and then copy it to /usr/bin or whatever and run it from there but idk. Thanks!