public function groupPostComments($pid, $options = ''){ 
		if(!is_string($pid)){
			throw new LinkedInException('LinkedIn->groupPostComments(): bad data passed, $pid must be of type string.');
		}
		if(!is_string($options)) {
			throw new LinkedInException('LinkedIn->groupPostComments(): bad data passed, $options must be of type string.');
		}		
		
		// construct and send the request
		$query    = self::_URL_API . '/v1/posts/' . trim($pid) . '/comments' . trim($options);
		$response = $this->fetch('GET', $query);

		/**
	   * Check for successful request (a 200 response from LinkedIn server) 
	   * per the documentation linked in method comments above.
	   */
		return $this->checkResponse(200, $response);
	}