Assign Roles to Multiple Users while seeding in Spatie Roles and Permissions package

Question

I need to assign roles to multiple users while seeding. Everything works fine for single user.

Code used

$roleName = 'Administrator';
        $role = Role::create(['name' => 'Administrator']);
        $permissions = Permission::pluck('id','id')->all();
        $role->syncPermissions($permissions);
$user = User::where('user_type', $roleName)->get();
 $user->assignRole([$role->id]);

This is getting error. When I used first() insted of get() it works fine for first user