Para alguns tipos de aplicação específicos você pode querer adicionar dependências para toda a aplicação.

De forma semelhante a [adicionar dependências (`dependencies`) em *decoradores de operação de rota*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, você pode adicioná-las à aplicação `FastAPI`.

Nesse caso, elas serão aplicadas a todas as *operações de rota* da aplicação:

//// tab | Python 3.9+

```Python hl_lines="16"

@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class MultiInputStream extends InputStream {

  private Iterator<? extends ByteSource> it;
  @CheckForNull private InputStream in;

  /**
   * Creates a new instance.
   *
   * @param it an iterator of I/O suppliers that will provide each substream
   */
  public MultiInputStream(Iterator<? extends ByteSource> it) throws IOException {
    this.it = checkNotNull(it);
    advance();
  }

    TreeMultimap<String, Integer> multimap = createPopulate();
    Iterator<Entry<String, Collection<Integer>>> iterator = multimap.asMap().entrySet().iterator();
    Entry<String, Collection<Integer>> entry = iterator.next();
    assertEquals("foo", entry.getKey());
    assertThat(entry.getValue()).containsExactly(1, 3, 7);
    entry = iterator.next();
    assertEquals("google", entry.getKey());

    }

    @Override
    public SortedMultiset<E> descendingMultiset() {
      return new StandardDescendingMultiset() {

        @Override
        Iterator<Entry<E>> entryIterator() {
          return backingMultiset.descendingMultiset().entrySet().iterator();
        }
      };
    }

    @Override
    public NavigableSet<E> elementSet() {
      return new StandardElementSet();
    }

    @Override

    StringSubscriber s2 = new StringSubscriber();
    ObjectSubscriber o1 = new ObjectSubscriber();

    Iterator<Subscriber> empty = registry.getSubscribers("");
    assertFalse(empty.hasNext());

    empty = registry.getSubscribers("");

    registry.register(s1);
    assertFalse(empty.hasNext());

    Iterator<Subscriber> one = registry.getSubscribers("");
    assertEquals(s1, one.next().target);

 * the License.
 */

package com.google.common.cache;

import com.google.common.annotations.GwtCompatible;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;

/**
 * The reason why a cached entry was removed.
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible

          }
        };

    final int numThreads = 10;
    final int iterations = 1000;
    Thread[] threads = new Thread[numThreads];
    for (int i = 0; i < numThreads; i++) {
      threads[i] =
          new Thread() {
            @Override
            public void run() {
              for (int j = 0; j < iterations; j++) {
                Object unused = Suppliers.synchronizedSupplier(nonThreadSafe).get();

          }
        };

    final int numThreads = 10;
    final int iterations = 1000;
    Thread[] threads = new Thread[numThreads];
    for (int i = 0; i < numThreads; i++) {
      threads[i] =
          new Thread() {
            @Override
            public void run() {
              for (int j = 0; j < iterations; j++) {
                Object unused = Suppliers.synchronizedSupplier(nonThreadSafe).get();

In this case, this `__call__` is what **FastAPI** will use to check for additional parameters and sub-dependencies, and this is what will be called to pass a value to the parameter in your *path operation function* later.

## Parameterize the instance

And now, we can use `__init__` to declare the parameters of the instance that we can use to "parameterize" the dependency:

 */
@Experimental
public interface DependencyResolver extends Service {

    /**
     * Collects the transitive dependencies of some artifacts and builds a dependency graph for the given path scope.
     * Note that this operation is only concerned about determining the coordinates of the transitive dependencies and
     * does not actually resolve the artifact files.
     *
     * @param session the {@link Session}, must not be {@code null}