docs: function initialize(config, callback, config_helper) {
    config_helper = config_helper || require('../config/index');
  
    if(!checkConfSanity(config)) {
      callback(new Error('conf.dbopt is not sane, can\'t initialize composite adapter'));
      return;
    }
  
    populateDatabasesArray(config, config_helper, function(err, databases) {
      if(err)
        return callback(err);
      var adapter = new Compositeadapter(config, databases);
      callback(null, adapter);
    });
  }