function setup_keypress() {
  document.onkeydown = function(e) {
    switch (e.keyCode) {
      {% if paginator.has_previous %}
      case 37: // left
        document.location.href = "{{ paginator.previous_path }}"; 
        break;
      {% endif %}
      case 38: // up
        document.location.href = "{{ paginator.single_page }}#{{ paginator.section_id }}"; 
        break;
      {% if paginator.has_next %}
      case 39: // right
        document.location.href = "{{ paginator.next_path }}"; 
        break;
      {% endif %}
    }
  }
}