I got an error prompt when I executed the `tmux` command <img width="483" alt="screen shot 2018-11-09 at 16 19 10" src="https://user-images.githubusercontent.com/23230442/48252246-2d5de180-e43f-11e8-87d9-ac072fd5139a.png"> The root cause is oh-my-zsh tmux plugin alias `tmux` to a shell function  The `canExecute` method return false in this case 
I got an error prompt when I executed the
tmuxcommandThe root cause is oh-my-zsh tmux plugin alias
tmuxto a shell functionThe
canExecutemethod return false in this case