ember sass import file with tilde

I'm trying to import in an ember project that uses ember-cli-sass a scss file from a node_package which imports another scss file from another node package using ~;

basically the file I'm importing contains the following instruction:

@import "~bootstrap/scss/functions"; // from bootstrap node_module

but that breaks the build since it seems that ember-cli is not resolving the ~;

I've configured ember-cli-build with

sassOptions: {
  includePaths: [
    'node_modules/<package_name>/scss',
  ]
},