* java.util.function.Supplier}, making conversion code necessary only in one direction. At that
 * time, this interface will be officially discouraged.
 *
 * @author Harry Heymann
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface Supplier<T extends @Nullable Object>
{
  /**

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

9. This *path operation function* is not returning dataclasses (although it could), but a list of dictionaries with internal data.

    // If the host exactly matches, we're done: this connection can carry the address.
    if (address.url.host == this.route().address.url.host) {
      return true // This connection is a perfect match.
    }

    // At this point we don't have a hostname match. But we still be able to carry the request if
    // our connection coalescing requirements are met. See also:

            plugins.forEach(p -> mergedPlugins.put(p.getPrefix(), p));
            metadata = metadata.withPlugins(mergedPlugins.values());
        }
        // just carry-on as-is
        if (recessive.getVersioning() != null) {
            metadata = metadata.withVersioning(recessive.getVersioning());
        }
    }

    @Deprecated
    @Override

            versions.addAll(original.getVersions());
            versioning.versions(new ArrayList<>(versions));
        }

        metadata = metadata.withVersioning(versioning.build());

        // just carry-on as-is
        if (recessive.getPlugins() != null && !recessive.getPlugins().isEmpty()) {
            metadata = metadata.withPlugins(new ArrayList<>(recessive.getPlugins()));
        }
    }

                }
            }
        }

        metadata = metadata.withVersioning(metadata.getVersioning().withSnapshotVersions(versions.values()));

        // just carry-on as-is
        if (recessive.getPlugins() != null && !recessive.getPlugins().isEmpty()) {
            metadata = metadata.withPlugins(new ArrayList<>(recessive.getPlugins()));
        }

        artifacts.clear();

                }
            }
        }

        metadata = metadata.withVersioning(metadata.getVersioning().withSnapshotVersions(versions.values()));

        // just carry-on as-is
        if (recessive.getPlugins() != null && !recessive.getPlugins().isEmpty()) {
            metadata = metadata.withPlugins(new ArrayList<>(recessive.getPlugins()));
        }
    }

        noMoreExchanges(null)
      }
    }
  }

  /**
   * Prepare for a potential trip through all of this call's network interceptors. This prepares to
   * find an exchange to carry the request.
   *
   * Note that an exchange will not be needed if the request is satisfied by the cache.
   *
   * @param newRoutePlanner true if this is not a retry and new routing can be performed.
   */

```Python hl_lines="7"
{!../../../docs_src/first_steps/tutorial003.py!}
```

!!! note
    Jeśli nie znasz różnicy, sprawdź [Async: *"In a hurry?"*](../async.md#in-a-hurry){.internal-link target=_blank}.

### Krok 5: zwróć zawartość

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

func (e stsErrorCodeMap) ToSTSErr(errCode STSErrorCode) STSError {
	apiErr, ok := e[errCode]
	if !ok {
		return e[ErrSTSInternalError]
	}
	return apiErr
}

// error code to STSError structure, these fields carry respective
// descriptions for all the error responses.
var stsErrCodes = stsErrorCodeMap{
	ErrSTSAccessDenied: {
		Code:           "AccessDenied",