In this case, you could want to document how that external API *should* look like. What *path operation* it should have, what body it should expect, what response it should return, etc.

## An app with callbacks

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

 * iterator} method only once, and should be tested using this class. Exceptions to this rule should
 * be clearly documented.
 *
 * <p>Note that although your APIs should be liberal in what they accept, your methods which
 * <i>return</i> iterables should make every attempt to return ones of the robust variety.
 *
 * <p>This testing utility is not thread-safe.
 *
 * @author Kevin Bourrillion

  - type: input
    id: package-path
    attributes:
      label: "What is the path of the package that you would like to have removed?"
      description: |
        We can remove packages with a shared path prefix.
        For example, a request for 'github.com/author' would remove all pkg.go.dev pages with that package path prefix.
    validations:
      required: true
  - type: textarea
    id: package-owner

For any non-trivial change, we need to be able to answer these questions:

* Why is this change done? What's the use case?
* For user facing features, what will the API look like?
* What test cases should it have? What could go wrong?
* How will it roughly be implemented? We'll happily provide code pointers to save you time.

name: Bug Report
description: Report a bug encountered while operating Kubernetes
labels: kind/bug
body:
  - type: textarea
    id: problem
    attributes:
      label: What happened?
      description: |
        Please provide as much info as possible. Not doing so may result in your bug not being addressed in a timely manner.
        If this matter is security related, please disclose it privately via https://kubernetes.io/security
    validations:

    validations:
      required: true

  - type: textarea
    attributes:
      label: Expected Behavior
      description: What did you expect to happen?
    validations:
      required: true

  - type: textarea
    attributes:
      label: Actual Behavior
      description: What actually happened?
    validations:
      required: true

  - type: dropdown
    attributes:
      label: Packages

 * iterator} method only once, and should be tested using this class. Exceptions to this rule should
 * be clearly documented.
 *
 * <p>Note that although your APIs should be liberal in what they accept, your methods which
 * <i>return</i> iterables should make every attempt to return ones of the robust variety.
 *
 * <p>This testing utility is not thread-safe.
 *
 * @author Kevin Bourrillion

### FastAPI Data Filtering

Now, for FastAPI, it will see the return type and make sure that what you return includes **only** the fields that are declared in the type.

			for _, sz := range test.sizes {
				h.add(sz)
			}
			got := h.toMap()
			exp := test.want
			// what is in exp is in got
			for k := range exp {
				if exp[k] != got[k] {
					t.Fatalf("interval %s: Expected %d values but got %d values\n", k, exp[k], got[k])
				}
			}
			// what is absent in exp is absent in got too
			for k := range got {
				if _, ok := exp[k]; !ok && got[k] > 0 {

## Containers and Processes

A **container image** normally includes in its metadata the default program or command that should be run when the **container** is started and the parameters to be passed to that program. Very similar to what would be if it was in the command line.

When a **container** is started, it will run that command/program (although you can override it and make it run a different command/program).