gistfile1.php

function test123_node_view(\Drupal\Core\Entity\EntityInterface $node, \Drupal\entity\Plugin\Core\Entity\EntityDisplay $display, $view_mode, $langcode) {                                                                                    
  dpm($node);                                                                                                           
} 

/*
Recoverable fatal error: Argument 1 passed to test123_node_view() must implement interface Drupal\Core\Entity\EntityInterface, array given in test123_node_view() (line 28 of modules/custom/test123/test123.module). 
*/