### Tags with Enums { #tags-with-enums }

If you have a big application, you might end up accumulating **several tags**, and you would want to make sure you always use the **same tag** for related *path operations*.

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

{* ../../docs_src/path_operation_configuration/tutorial002b_py310.py hl[1,8:10,13,18] *}

        @Test
        @DisplayName("should compare versions correctly")
        void shouldCompareVersionsCorrectly() {
            // Based on the actual implementation, it only handles specific cases
            assertTrue(ModelVersionUtils.isVersionGreaterOrEqual("4.1.0", "4.1.0"));
            assertFalse(ModelVersionUtils.isVersionGreaterOrEqual("4.0.0", "4.1.0"));

//
// This allows us to hide concrete implementations of TensorHandle from header
// files. The interface lists the common functionality that must be provided by
// any concrete implementation. However, in cases where the true concrete class
// is needed a static_cast can be applied.
class ImmediateExecutionTensorHandle : public AbstractTensorHandle {
 public:
  // Returns number of dimensions.

In these cases you can use `root_path` to configure your application.

The `root_path` is a mechanism provided by the ASGI specification (that FastAPI is built on, through Starlette).

The `root_path` is used to handle these specific cases.

And it's also used internally when mounting sub-applications.

        // Ordinal is consistent with declaration order
        switch (name) {
        case "NONE":
            assertEquals(0, rp.ordinal());
            break;
        case "NO_TIMEOUT":
            assertEquals(1, rp.ordinal());
            break;
        case "NO_RETRY":
            assertEquals(2, rp.ordinal());
            break;
        case "RETAIN_PAYLOAD":
            assertEquals(3, rp.ordinal());
            break;

 * recommended that the caller does not persist a reference to the backing map (unless the backing
 * map is immutable).
 *
 * <p>This class is tailored toward use cases in common.graph. It is *NOT* a general purpose map.
 *
 * @author James Sexton
 */
class MapIteratorCache<K, V> {
  private final Map<K, V> backingMap;

  /*

        assertEscaping(xmlEscaper, "\uFFFD", ch);
      }
    }

    // Test _all_ allowed characters (including surrogate values).
    for (char ch = 0x20; ch <= 0xFFFD; ch++) {
      // There are a small number of cases to consider, so just do it manually.
      if (ch == '&') {
        assertEscaping(xmlEscaper, "&amp;", ch);
      } else if (ch == '<') {
        assertEscaping(xmlEscaper, "&lt;", ch);
      } else if (ch == '>') {

   * those sublists might implement a private {@code MySubList} type but serialize as a plain {@code
   * MyList} to save space. So long as {@code MyList} has all the public supertypes of {@code
   * MySubList}, this is safe. For these cases, for which {@code reserializeAndAssert} is too
   * strict, use {@link #reserialize}.
   *
   * @return the re-serialized object
   * @throws RuntimeException if the specified object was not successfully serialized or

/// tip

Here we use [`time.perf_counter()`](https://docs.python.org/3/library/time.html#time.perf_counter) instead of `time.time()` because it can be more precise for these use cases. 🤓

///

## Multiple middleware execution order { #multiple-middleware-execution-order }

This also means that in many cases you can pass the same object you get from a request **directly to the database**, as everything is validated automatically.

The same applies the other way around, in many cases you can just pass the object you get from the database **directly to the client**.