Terminal / vim / shortcuts

[Daniel Underwood]

I edit python code in vim using Terminal on xfce.  I find myself, not
surprisingly, having to exit "insert mode" and save changes frequently
(when making code changes and wishing to test the immediate effects of
the changes in a separate terminal).  This requires pressing 4 keys:
"esc", ":", "w", and "enter".  How can I configure a shortcut (ideally
using an F# key) that will perform this sequence of 4 key-presses?

TIA,
Daniel