Opacify function returning unmodified hex

I seem to have run into something strange with sass. I'm trying to get a 95% opaque version of `#111111` but it seems that the `opacify` function isn't returning the correct value. When I use the code below, the compiled stylesheet sets the `background-color` to `#111111`. I'm using `opacify` because the color is being stored as a variable in hex and cannot be modified through standard `rgba` if I want to continue using the variables. Code below: ``` $midnight: #111111; .some-container { background-color: opacify($midnight,0.95); } ```