Got build error after installing paper-ember and serving ember

after `yarn add -D ember-paper` and ember serve. I did not do `ember install ember-paper` because i have `ember-cli-sass` installed already. So i added this manually to the app.scss file instead `@import 'ember-paper';` Got this error below.

Sass Syntax Error (SassCompiler) in app/styles/color-palette.scss:460:10

Error: argument `$map1` of `map-merge($map1, $map2)` must be a map
on line 460 of tmp/sass_compiler-input_base_path-AcmabCvz.tmp/app/styles/color-palette.scss, in function `map-merge`
from line 460 of tmp/sass_compiler-input_base_path-AcmabCvz.tmp/app/styles/color-palette.scss
from line 63 of tmp/sass_compiler-input_base_path-AcmabCvz.tmp/app/styles/ember-paper.scss
from line 78 of tmp/sass_compiler-input_base_path-AcmabCvz.tmp/app/styles/app.scss
>> $colors: map-merge($colors,(

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