import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEY_QUERIES;

import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.testing.Helpers.mapEntry;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_REMOVE;
import static java.util.Collections.singleton;
import static java.util.Collections.singletonMap;

import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.testing.Helpers.mapEntry;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_REMOVE;
import static java.util.Collections.singleton;
import static java.util.Collections.singletonMap;

 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;

import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;

  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;

  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;

    assertContentsAnyOrder(result, v0());
  }

  @CollectionSize.Require(SEVERAL)
  public void testGetMultiple() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k0(), v1()), mapEntry(k0(), v2()));
    assertGet(k0(), v0(), v1(), v2());
  }

  public void testGetAbsentKey() {
    assertGet(k4());
  }

  @CollectionSize.Require(SEVERAL)
  @MapFeature.Require(SUPPORTS_REMOVE)

///

### Flask REST frameworks { #flask-rest-frameworks }

There are several Flask REST frameworks, but after investing the time and work into investigating them, I found that many are discontinued or abandoned, with several standing issues that made them unfit.

### [Marshmallow](https://marshmallow.readthedocs.io/en/stable/) { #marshmallow }

## Integrated middlewares { #integrated-middlewares }

**FastAPI** includes several middlewares for common use cases, we'll see next how to use them.

/// note | Technical Details

For the next examples, you could also use `from starlette.middleware.something import SomethingMiddleware`.