<===> input.scss
a {
  @each $number in 1px 2px 3px 4px {
    b: $number;
  }
}
c {
  @each $str in foo, bar, baz, bang {
    d: $str;
  }
}

<===> output.css
a {
  b: 1px;
  b: 2px;
  b: 3px;
  b: 4px;
}

c {
  d: foo;
  d: bar;
  d: baz;
  d: bang;
}