An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

You probably want to test the external provider once, but not necessarily call it for every test that runs.

# Sub-dependencies

You can create dependencies that have **sub-dependencies**.

They can be as **deep** as you need them to be.

**FastAPI** will take care of solving them.

## First dependency "dependable"

You could create a first dependency ("dependable") like:

//// tab | Python 3.10+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py310.py!}
```

////

//// tab | Python 3.9+

		// Leader node (that successfully acquires the lock inside runCallhome)
		// will keep performing the callhome. If the leader goes down for some reason,
		// the lock will be released and another node will acquire it and take over
		// because of this loop.
		for {
			if !globalCallhomeConfig.Enabled() {
				return
			}

			if !runCallhome(ctx, objAPI) {
				// callhome was disabled or context was canceled
				return
			}

# Python Types Intro

Python has support for optional "type hints" (also called "type annotations").

These **"type hints"** or annotations are a special syntax that allow declaring the <abbr title="for example: str, int, float, bool">type</abbr> of a variable.

By declaring types for your variables, editors and tools can give you better support.

	}
	AssertEqual(t, find1, value)
}

func TestEmbedPreload(t *testing.T) {
	type Country struct {
		ID   int `gorm:"primaryKey"`
		Name string
	}
	type EmbeddedAddress struct {
		ID        int
		Name      string
		CountryID *int
		Country   *Country
	}
	type NestedAddress struct {
		EmbeddedAddress
	}
	type Org struct {
		ID              int

			agreed: func(entry metaCacheEntry) {
				jt.Take()
				go healEntry(bucket, entry)
			},
			partial: func(entries metaCacheEntries, _ []error) {
				entry, ok := entries.resolve(&resolver)
				if !ok {
					// check if we can get one entry at least
					// proceed to heal nonetheless.
					entry, _ = entries.firstFound()
				}
				jt.Take()
				go healEntry(bucket, *entry)
			},

   * that conversion is safe.
   *
   * <p>This method is intended to help with usages of type parameters that have {@linkplain
   * ParametricNullness parametric nullness}. If a type parameter instead ranges over only non-null
   * types (or if the type is a non-variable type, like {@code String}), then code should almost
   * never use this method, preferring instead to call {@code requireNonNull} so as to benefit from

    theta_inputs[input_index] = thetaMinus.get();
    TF_RETURN_IF_ERROR(
        RunAndMaybeSum(ctx, forward, theta_inputs, f_outputs, use_function));
    AbstractTensorHandlePtr fMinus(f_outputs[0]);

    // Take Difference of both estimates: (f(theta + eps) - f(theta - eps)).
    TF_RETURN_IF_ERROR(
        ops::Sub(ctx, fPlus.get(), fMinus.get(), f_outputs, "sub_top"));
    AbstractTensorHandlePtr fDiff(f_outputs[0]);

  - url: https://www.svix.com/
    title: Svix - Webhooks as a service
    img: https://fastapi.tiangolo.com/img/sponsors/svix.svg
  - url: https://www.codacy.com/?utm_source=github&utm_medium=sponsors&utm_id=pioneers
    title: Take code reviews from hours to minutes
    img: https://fastapi.tiangolo.com/img/sponsors/codacy.png
  - url: https://www.stainlessapi.com/?utm_source=fastapi&utm_medium=referral
    title: Stainless | Generate best-in-class SDKs

  professional setting

## Our Responsibilities

Project maintainers are responsible for clarifying the standards of acceptable
behavior and are expected to take appropriate and fair corrective action in
response to any instances of unacceptable behavior, in compliance with the
licensing terms applying to the Project developments.