code: function(context, parentPkg, childPkg, isRoot){
  		var pkg = parentPkg;
  		var isFlat = context.isFlatFileStructure;
  
  		// if a peer dependency, and not isRoot
  		if(childPkg._isPeerDependency && !isRoot ) {
  			// check one node_module level higher
  			childPkg.origFileUrl = nodeModuleAddress(pkg.fileUrl)+"/"+childPkg.name+"/package.json";
  		} else if(isRoot) {
  			childPkg.origFileUrl = utils.path.depPackage(pkg.fileUrl, childPkg.name);
  		} else {
  			// npm 2
  			childPkg.origFileUrl = childPkg.nestedFileUrl =
  				utils.path.depPackage(pkg.fileUrl, childPkg.name);
  
  			if(isFlat) {
  				// npm 3
  				childPkg.origFileUrl = crawl.parentMostAddress(context,
  															   childPkg);
  			}
  		}
  
  		// check if childPkg matches a parent's version ... if it
  		// does ... do nothing
  		if(crawl.hasParentPackageThatMatches(context, childPkg)) {
  			return;
  		}
  
  		if(crawl.isSameRequestedVersionFound(context, childPkg)) {
  			return;
  		}
  
  		var requestedVersion = childPkg.version;
  		return npmLoad(context, childPkg, requestedVersion)
  		.then(function(pkg){
  			crawl.setVersionsConfig(context, pkg, requestedVersion);
  			return pkg;
  		});
  	}
docs: Fetch a particular package.json dependency
  @param {Object} context
  @param {NpmPackage} parentPkg
  @param {NpmPackage} childPkg
  @param {Boolean} [isRoot] If the root module's dependencies shoudl be crawled.
  @return {Promise} A promise when the package has loaded