e := f.updateCache.find(parent.Key())
					if e == nil || e.Compacted {
						foundAny = true
						break
					}
					next := f.updateCache.searchParent(parent)
					if next == nil {
						foundAny = true
						break
					}
					parent = *next
				}
				if !foundAny {
					// Add non-compacted empty entry.
					f.updateCache.replaceHashed(h, &thisHash, dataUsageEntry{})
				}
			}

I'll show you some concrete examples in the next chapters.

---

Then the next concepts to consider are all about the program running your actual API (e.g. Uvicorn).

## Program and Process

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

## Documenting the callback

The actual callback code will depend heavily on your own API app.

And it will probably vary a lot from one app to the next.

It could be just one or two lines of code, like:

```Python
callback_url = "https://example.com/api/v1/invoices/events/"

## Environment Variables

!!! tip
    If you already know what "environment variables" are and how to use them, feel free to skip to the next section below.

    Copy **only** the file with the requirements first, not the rest of the code.

    As this file **doesn't change often**, Docker will detect it and use the **cache** for this step, enabling the cache for the next step too.

4. Install the package dependencies in the requirements file.

mpl.class package org.codehaus.plexus.util; final synchronized class FastMap$EntryImpl implements java.util.Map$Entry { private Object _key; private Object _value; private int _index; private FastMap$EntryImpl _previous; private FastMap$EntryImpl _next; private FastMap$EntryImpl _before; private FastMap$EntryImpl _after; private void FastMap$EntryImpl(); public Object getKey(); public Object getValue(); public Object setValue(Object); public boolean equals(Object); public int hashCode(); public String...

	for {
		select {
		case <-ctx.Done():
			return
		case <-monitor.C:
			if serverDebugLog {
				console.Debugln("running drive monitoring")
			}

			s.connectDisks()

			// Reset the timer for next interval
			monitor.Reset(monitorInterval)
		}
	}
}

func (s *erasureSets) GetLockers(setIndex int) func() ([]dsync.NetLocker, string) {
	return func() ([]dsync.NetLocker, string) {

	if conf.PrevResult == nil {
		result = &cniv1.Result{
			CNIVersion: cniv1.ImplementedSpecVersion,
		}
		return types.PrintResult(result, conf.CNIVersion)
	}

	// Pass through the result for the next plugin
	return types.PrintResult(conf.PrevResult, conf.CNIVersion)
}

func CmdCheck(args *skel.CmdArgs) (err error) {
	return nil
}

func CmdDelete(args *skel.CmdArgs) (err error) {
	return nil
}

* Memory
* Previous steps before starting

		}
		pi, err := pool.PutObjectPart(ctx, bucket, object, uploadID, partID, data, opts)
		if err == nil {
			return pi, nil
		}
		if _, ok := err.(InvalidUploadID); ok {
			// Look for information on the next pool
			continue
		}
		// Any other unhandled errors such as quorum return.
		return PartInfo{}, err
	}

	return PartInfo{}, InvalidUploadID{
		Bucket:   bucket,
		Object:   object,