Sass helpers for keyframes animation

keyframes_animation.sass

=keyframes($name)
  @-webkit-keyframes #{$name}
    @content
  @-moz-keyframes #{$name}
    @content
  @keyframes #{$name}
    @content

=animation($name, $duration)
  -webkit-animation-name: #{$name}
  -webkit-animation-duration: #{$duration}
  -moz-animation-name: #{$name}
  -moz-animation-duration: #{$duration}
  animation-name: #{$name}
  animation-duration: #{$duration}