550e8400-e29b-41d4-a716-446655440000 (Valid UUID v4)
6ba7b810-9dad-11d1-80b4-00c04fd430c8 (Valid UUID v1)
550e8400e29b41d4a716446655440000 (UUID without hyphens)
invalid-uuid-format-12345 (Invalid format)
00000000-0000-0000-0000-000000000000 (Nil UUID)