How to modify the root parent selector in sass -

this question has answer here:

how can modify root element of parent selector chain? (using sass 3.3.x) like...

=prepend($prefix)   @at-root .#{$prefix}#{&}   // note there no dot (.) separating     @content  .foo   .bar     +prepend(baz)       background: red

and return

.baz.foo .bar {   background: red; }

or better... explicit way target root element (or nth element)?

=prepend($prefix)   &.#{$prefix}     @content  .foo   +prepend("baz")     .bar       background: red

returns this:

.foo.baz .bar {   background: red; }

on right track?

HR