code: public function fromPost($param = null, $default = null)
      {
          if ($param === null) {
              return $this->event->getRequest()->getPost($param, $default)->toArray();
          }
      
          return $this->event->getRequest()->getPost($param, $default);
      }
docs: Return all post parameters or a single post parameter.
  
  @param string $param Parameter name to retrieve, or null to get all.
  @param mixed $default Default value to use when the parameter is missing.
  @return mixed