* <ul>
   *   <li>All visible static methods are checked such that passing null for any parameter that's
   *       not annotated nullable (according to the rules of {@link NullPointerTester}) should throw
   *       {@link NullPointerException}.
   *   <li>If there is any visible constructor or visible static factory method declared by the
   *       class, all visible instance methods will be checked too using the instance created by

        ServerMessageBlock msg = (ServerMessageBlock) m;

        if ( ( msg.getFlags2() & SmbConstants.FLAGS2_SECURITY_SIGNATURES ) == 0 ) {
            // signature requirements need to be checked somewhere else
            log.warn("Expected signed response, but is not signed");
            return false;
        }

        update(this.macSigningKey, 0, this.macSigningKey.length);
        int index = offset;

      for (T element : initialContents) {
        queue.offer(element);
      }
      return queue;
    }

    @SuppressWarnings("unchecked") // safe "contravariant cast"
    private <T extends B> Ordering<T> ordering() {
      return Ordering.from((Comparator<T>) comparator);
    }
  }

  private final Heap minHeap;
  private final Heap maxHeap;

    public String getMethodName() {
        return methodName;
    }

    @Override
    public Class<?>[] getParameterTypes() {
        return parameterTypes;
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> Class<T> getReturnType() {
        return (Class<T>) returnType;
    }

    @Override
    public boolean isPublic() {
        return MethodUtil.isPublic(method);
    }

```Python hl_lines="16"
{!../../docs_src/dependencies/tutorial011.py!}
```

这样就可以**参数化**依赖项，它包含 `checker.fixed_content` 的属性 - `"bar"`。

## 把实例作为依赖项

然后，不要再在 `Depends(checker)` 中使用 `Depends(FixedContentQueryChecker)`， 而是要使用 `checker`，因为依赖项是类实例 - `checker`，不是类。

处理依赖项时，**FastAPI** 以如下方式调用 `checker`：

```Python
checker(q="somequery")
```

……并用*路径操作函数*的参数 `fixed_content_included` 返回依赖项的值：

```Python hl_lines="20"

  /**
   * Returns the empty bimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  // Casting to any type is safe because the set will never hold any elements.
  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableBiMap<K, V> of() {
    return (ImmutableBiMap<K, V>) RegularImmutableBiMap.EMPTY;
  }

  /** Returns an immutable bimap containing a single entry. */

      Iterables.removeIf(unfiltered, predicate);
    }

    @Override
    public boolean contains(@CheckForNull Object element) {
      if (safeContains(unfiltered, element)) {
        @SuppressWarnings("unchecked") // element is in unfiltered, so it must be an E
        E e = (E) element;
        return predicate.apply(e);
      }
      return false;
    }

    @Override

  }

  @Override
  public final ListMultimap<String, String> create(Object... entries) {
    @SuppressWarnings("unchecked")
    Entry<String, String>[] array = (Entry<String, String>[]) new Entry<?, ?>[entries.length];
    int i = 0;
    for (Object o : entries) {
      @SuppressWarnings("unchecked")
      Entry<String, String> e = (Entry<String, String>) o;
      array[i++] = e;
    }
    return create(array);
  }

  }

  @Override
  public final SetMultimap<String, String> create(Object... entries) {
    @SuppressWarnings("unchecked")
    Entry<String, String>[] array = (Entry<String, String>[]) new Entry<?, ?>[entries.length];
    int i = 0;
    for (Object o : entries) {
      @SuppressWarnings("unchecked")
      Entry<String, String> e = (Entry<String, String>) o;
      array[i++] = e;
    }
    return create(array);
  }

    }

    @Override
    @SuppressWarnings({"unchecked"})
    public <T> T computeIfAbsent(String groupId, String artifactId, String version, String tag, Supplier<T> data) {
        return (T) computeIfAbsent(new GavCacheKey(groupId, artifactId, version, tag), data);
    }

    @Override
    @SuppressWarnings({"unchecked"})
    public <T> T computeIfAbsent(Source path, String tag, Supplier<T> data) {