# Dependencies with yield

FastAPI supports dependencies that do some <abbr title='sometimes also called "exit code", "cleanup code", "teardown code", "closing code", "context manager exit code", etc.'>extra steps after finishing</abbr>.

To do this, use `yield` instead of `return`, and write the extra steps (code) after.

/// tip

Make sure to use `yield` one single time per dependency.

///

/// note | "Technical Details"

			i, err = d.objectOrdered()
		} else {
			i, err = d.object()
		}
		return i, Object, err
	default:
		return nil, Unknown, d.mkError(ErrSyntax, "looking for beginning of value")
	}
}

// string called by `any` or `object`(for map keys) after reading `"`
func (d *Decoder) string() (string, error) {
	d.scratch.reset()
	c := d.next()

scan:
	for {
		switch {
		case c == '"':

  tensorflow::unwrap(ctx)->SetThreadLocalDevicePlacementPolicy(
      static_cast<tensorflow::ContextDevicePlacementPolicy>(policy));
}

// Note: this function looks up a thread local policy. So it should be called in
// the appropriate client thread. In particular, in async mode, it may not be
// safe to call this function from the async EagerExecutor threads.
extern TFE_ContextDevicePlacementPolicy TFE_ContextGetDevicePlacementPolicy(

if (isBrowser && navigator.userAgent.indexOf(longerTimeoutBrowsers[i]) >= 0) {\n      return 1;\n    }\n  }\n  return 0;\n}());\n\nexport function microtaskDebounce(fn) {\n  let called = false\n  return () => {\n    if (called) {\n      return\n    }\n    called = true\n    window.Promise.resolve().then(() => {\n      called = false\n      fn()\n    })\n  }\n}\n\nexport function taskDebounce(fn) {\n  let scheduled = false;\n  return () => {\n    if (!scheduled) {\n      scheduled = true;\n      setTimeout(()...

	// "SCHILY.xattr." namespace.
	//
	// The following are semantically equivalent:
	//  h.Xattrs[key] = value
	//  h.PAXRecords["SCHILY.xattr."+key] = value
	//
	// When Writer.WriteHeader is called, the contents of Xattrs will take
	// precedence over those in PAXRecords.
	//
	// Deprecated: Use PAXRecords instead.
	Xattrs map[string]string

	// PAXRecords is a map of PAX extended header records.
	//

                    return this.handle.acquire();
                }

                // TODO: wait for pipe, still not sure when this needs to be called exactly
                if ( this.uncPath.startsWith("\\pipe\\") ) {
                    th.send(new TransWaitNamedPipe(th.getConfig(), this.uncPath), new TransWaitNamedPipeResponse(th.getConfig()));
                }

 *
 * The full range of code points is 0..0x10fffe. We can represent any of these code points with 21
 * bits.
 *
 * We split each code point into a 14-bit prefix and a 7-bit suffix. All code points with the same
 * prefix are called a 'section'. There are 128 code points per section.
 *
 * Ranges Data (32,612 bytes)
 * ==========================
 *
 * Each entry is 4 bytes, and represents a _range_ of code points that all share a common 14-bit

		pi, k8sErr = getK8sPodInfo(kClient, podName, podNamespace)
		if k8sErr == nil {
			break
		}
		log.Debugf("Failed to get %s/%s pod info: %v", podNamespace, podName, k8sErr)
		time.Sleep(podRetrievalInterval)
	}
	if k8sErr != nil {
		log.Errorf("Failed to get %s/%s pod info: %v", podNamespace, podName, k8sErr)
		return k8sErr
	}

      startUpCalled = true;
      throw new UnsupportedOperationException("kaboom!");
    }

    @Override
    protected void run() {
      throw new AssertionError("run() should not be called");
    }

    @Override
    protected Executor executor() {
      return exceptionCatchingExecutor;
    }
  }

  public void testServiceThrowOnRun() throws Exception {

    }

    @Override
    public void xsetPaging(boolean paging) {
        // Do nothing because this is unsupported on ConditionBean.
        // And it is possible that this method is called by PagingInvoker.
    }

    @Override
    public void enablePagingCountLater() {
        // nothing
    }

    @Override
    public void disablePagingCountLater() {
        // nothing
    }