code: function getAtrule() {
    const childType = tokens[pos].atrule_type;
  
    if (childType === 1) return getAtruler(); // @-rule with ruleset
    if (childType === 2) return getAtruleb(); // Block @-rule
    if (childType === 3) return getAtrules(); // Single-line @-rule
    if (childType === 4) return getKeyframesRule();
  }
docs: Gets node with @-rule.
  
  @return {!Node}