code: function(attrs) {
              if (_.isEmpty(attrs)) return [];
              return this.filter(function(model) {
                  for (var key in attrs) {
                    if (attrs[key] !== model.get(key)) return false;
                  }
                  return true;
              });
          }
docs: Return models with matching attributes. Useful for simple cases of `filter`.
  
  @method where
  @return {Array} Array of models