code: function ES6ImportsRenamer(config, callback) {
  	config = config || {};
  
  	this._basePath = config.basePath;
  	this._renameDependencies = config.renameDependencies;
  	this._renameFn = config.renameFn;
  	this._callback = callback;
  	this._addedMap = {};
  
  	this._initStack(config.sources || []);
  	this._renameNextAst();
  }
docs: Class responsible for renaming import paths present in both the
  given source files and their dependencies, according to the
  given rename function.
  @param {{sources: !Array<{ast: !Object, path: string}>, basePath: ?string}} config
  @param {function(Error, Array)} callback Function to be called when the renaming
  is done.
  @constructor