{* ../../docs_src/query_params/tutorial004_py310.py hl[6,8] *}

## Required query parameters { #required-query-parameters }

When you declare a default value for non-path parameters (for now, we have only seen query parameters), then it is not required.

If you don't want to add a specific value but just make it optional, set the default as `None`.

We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

   * errors, for better performance.
   *
   * <p>For a new instance, where the arrays above have not yet been allocated, the value of {@code
   * metadata} is the size that the arrays should be allocated with. Once the arrays have been
   * allocated, the value of {@code metadata} combines the number of bits in the "short hash", in

<img src="/img/tutorial/path-operation-advanced-configuration/image01.png">

And if you see the resulting OpenAPI (at `/openapi.json` in your API), you will see your extension as part of the specific *path operation* too:

```JSON hl_lines="22"
{
    "openapi": "3.1.0",
    "info": {
        "title": "FastAPI",

        } else {
            this.createOptions = createOptions;
        }
        this.impersonationLevel = 0x02; // As seen on NT :~)
        this.securityFlags = (byte) 0x03; // SECURITY_CONTEXT_TRACKING | SECURITY_EFFECTIVE_ONLY
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.internal.smb1.ServerMessageBlock#getResponse()
     */
    @Override

        // Reserved (4 bytes) - The implementation skips writing these bytes,
        // so they will have the initial pattern (0xCCCCCCCC)
        // This is expected behavior as seen in the implementation at line 131
        assertEquals((byte) 0xCC, buffer[4]);
        assertEquals((byte) 0xCC, buffer[5]);
        assertEquals((byte) 0xCC, buffer[6]);
        assertEquals((byte) 0xCC, buffer[7]);

The important thing to keep in mind is that the `sub` key should have a unique identifier across the entire application, and it should be a string.

## Check it { #check-it }

Run the server and go to the docs: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

You'll see the user interface like:

FC1C          ; mapped                 ; 0633 062C     # 1.1  ARABIC LIGATURE SEEN WITH JEEM ISOLATED FORM
FC1D          ; mapped                 ; 0633 062D     # 1.1  ARABIC LIGATURE SEEN WITH HAH ISOLATED FORM
FC1E          ; mapped                 ; 0633 062E     # 1.1  ARABIC LIGATURE SEEN WITH KHAH ISOLATED FORM
FC1F          ; mapped                 ; 0633 0645     # 1.1  ARABIC LIGATURE SEEN WITH MEEM ISOLATED FORM

   * errors, for better performance.
   *
   * <p>For a new instance, where the arrays above have not yet been allocated, the value of {@code
   * metadata} is the size that the arrays should be allocated with. Once the arrays have been
   * allocated, the value of {@code metadata} combines the number of bits in the "short hash", in

| `minio_replication_max_active_workers`            | Maximum number of active replication workers seen since server start. <br><br>Type: gauge   | `server` |
| `minio_replication_max_queued_bytes`              | Maximum number of bytes queued for replication since server start. <br><br>Type: gauge      | `server` |