Compatible error in ActionMapping::action()

[UnnikrishnanBhargavakurup]

I'm getting the following error when I tried to implement ActionMapping.

MyActionMapping::action() must be compatible with Tgallice\\Wit\\ActionMapping::action($sessionId, $actionName, Tgallice\\Wit\\Model\\Context $context, array $entities = Array)

I implemented the function as you mentioned in the example:

public function action($sessionId, Context $context, Action $step)

Also i tried

public function action($sessionId, $actionName, \Tgallice\Wit\Model\Context $context, $entities = array()

What could be wrong here? My php version is 5.6.27

Thanks,
Unnikrishnan B.