original_string: protected function preAssert(
          Acl $acl,
          RoleInterface $role = null,
          ResourceInterface $resource = null,
          $privilege = null
      ) {
          return null;
      }
code: protected function preAssert(
          Acl $acl,
          RoleInterface $role = null,
          ResourceInterface $resource = null,
          $privilege = null
      ) {
          return null;
      }
code_tokens: protected function preAssert ( Acl $ acl , RoleInterface $ role = null , ResourceInterface $ resource = null , $ privilege = null ) { return null ; }
docstring: Overwrite this to check some conditions before the event is triggered.
  
  If this method returns a boolean value, this value will be returned as the assertions' result and
  no event will be triggered.
  
  @param Acl               $acl
  @param RoleInterface     $role
  @param ResourceInterface $resource
  @param null|string       $privilege
  
  @return null|bool
docstring_tokens: Overwrite this to check some conditions before the event is triggered .