Jade, mixins and extend

Given the following

/layouts
   main.jade
/partials
   some.jade
index.jade

Code in main.jade

html
    head
        title Layout page
    body
        block content

Code in some.jade

mixin list( title )
    h1 title
    ul
        li foo
        li bar
        li baz

Code in index.jade

extend ./layouts/main
extend ./partials/some
block content
    h1 Hello world
    +list( 'Ciao mondo' )

I'd like to know if there's some way to do something similar to this but that run without problem

Try replacing

extend ./layouts/main
extend ./partials/some
block content
    h1 Hello world
    +list( 'Ciao mondo' )

with

extend ./layouts/main
include ./partials/some  //note this line!
block content
    h1 Hello world
    +list( 'Ciao mondo' )