code: public function grant($permission)
      {
          if ($this->hasPermission($permission)) {
              return true;
          }
  
          if (!array_key_exists($permission, Gate::abilities())) {
              abort(403, 'Unknown permission');
          }
  
          return Permission::create([
              'role_id' => $this->id,
              'permission_slug' => $permission,
          ]);
  
          return false;
      }
docs: Give Permission to a Role
  
  @param string $permission
  @return boolean