What is the best way to do inheritance for rare elements in Ruby Sass?

Question

Sass

What is the best way to do inheritance for rare elements in Ruby Sass?
For example, for each .page__mainimgthere will be the same background properties (position, size, repaet), but the value of the url property will be different on the pages depending on the location in the block with the corresponding name.

.page {
  &__mainimg {
    @include background-image(center, cover, no-repeat);
    min-height: 500px;
  }
}
#main_page {
  .page__mainimg {
    background-image: url("/img/mainimg.jpg");
  }
}

How can this be written more compactly?