/**
  * Dynamically call methods
  * @param  string $method
  * @param  array  $params
  * @throws LaravelExcelException
  * @return LaravelExcelWriter
  */
 public function __call($method, $params)
 {
     // If the dynamic call starts with "set"
     if (starts_with($method, 'set') && $this->excel->isChangeableProperty($method)) {
         $this->_setAttribute($method, $params);
         return $this;
     } elseif (method_exists($this->excel, $method)) {
         // Call the method from the excel object with the given params
         $return = call_user_func_array(array($this->excel, $method), $params);
         return $return ? $return : $this;
     }
     throw new LaravelExcelException('[ERROR] Writer method [' . $method . '] does not exist.');
 }