code: function buildDescriptor(node, blueprintKey, descriptor /*, descriptorBuilder*/) {
      if (typeof descriptor.setup === 'function') {
        descriptor.setup(node, blueprintKey);
      }
  
      if (descriptor.value) {
        defineProperty(node, blueprintKey, descriptor.value);
      } else {
        defineProperty(node, blueprintKey, undefined, function() {
          return descriptor.get.call(this, blueprintKey);
        });
      }
    }
docs: Default `Descriptor` builder
  
  @param {TreeNode} node - parent node
  @param {String} blueprintKey - key to build
  @param {Descriptor} descriptor - descriptor to build
  @param {Function} defaultBuilder - default function to build this type of node
  
  @return undefined