code: function(ast) {
      let value = this.value;
  
      ast.traverse(function(node) {
        // If found block node stop at the next one for space check
        if (!node.is('block') && !node.is('atrulers')) return;
  
        if (node.first() &&
            node.first().is('space')) {
          node.first().content = value;
        } else if (value !== '') {
          var space = gonzales.createNode({
            type: 'space',
            content: value
          });
          node.insert(0, space);
        }
      });
    }
docs: Processes tree node.
  
  @param {node} ast