Thanks for pointing that out.  I do not want to be changing constants.

sample is not viable here because its ability to choose unique values is limited to one invocation; that is, arr.sample(3) will give me 3 distinct samples, but arr.sample; arr.sample; arr.sample will not.  Since add_robot_player can be called at distinct times, I need something with a little more persistence.

I settled on an instance variable that I refresh at initialization with the constant array.  As long as the max number of players is fewer than the list of names, it should safely serve the purpose.  Let me know if you see issues with this approach.