python expression is invalid (noob)

[Qhao]

I followed this step
And add the following configuration in your .vimrc
let g:python3_host_prog=/path/to/python/executable/

And I got this:
Error detected while processing /Users/abc/.vimrc:
line 8:
E15: Invalid expression: /path/to/python/executable/

how to solve it, thanks

[chtenb]

/path/to/python/executable/ has to point to your python installation, don't use that literal string.