Generated by SassMeister.com.

SassMeister-input.sass

// ----
// Sass (v3.3.8)
// Compass (v1.0.0.alpha.19)
// ----

%mix-in
  width: 75%
  height: 25%
  
=default-box($argument, $argument2)
  @extend %mix-in
  border: 1px solid blue
  border-radius: 2px solid green
  
.class1
  +default-box(red, black)
  
.class2
  +default-box(orange, purple)

SassMeister-output.css

.class1, .class2 {
  width: 75%;
  height: 25%;
}

.class1 {
  border: 1px solid blue;
  border-radius: 2px solid green;
}

.class2 {
  border: 1px solid blue;
  border-radius: 2px solid green;
}