How to use vi mode in fish shell? [closed]

I saw vi-mode implementation for fish shell, but I have no clue how to use it. Is there any tutorial available online describing basic functionality, e.g. how to switch modes?

In fish 2.3.0 and later:

• Run fish_vi_key_bindings to start vi mode
• Run fish_default_key_bindings to go back to default mode

If you want to make it the default, add the fish_vi_key_bindings command to ~/.config/fish/config.fish.

I am using fish 2.2.0. The following worked for me:

Edit $HOME/.config/fish/functions/fish_user_key_bindings.fish

function fish_user_key_bindings
  fish_vi_key_bindings
end

via this