All the dependencies we have seen are a fixed function or class.

But there could be cases where you want to be able to set parameters on the dependency, without having to declare many different functions or classes.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

But we want to be able to parameterize that fixed content.

## A "callable" instance

                available, instead of erroring out, the dependency result will be
                `None`.

                This is useful when you want to have optional authentication.

                It is also useful when you want to have authentication that can be
                provided in one of multiple optional ways (for example, in a query
                parameter or in an HTTP Bearer token).

	if err != nil {
		t.Fatalf("Stat failed: %v", err)
	}
	if !os.SameFile(fi1, fi2) {
		t.Fatalf("addr2line_test.go and %s are not same file", srcPath)
	}
	if want := "102"; srcLineNo != want {
		t.Fatalf("line number = %v; want %s", srcLineNo, want)
	}
}

// This is line 101. The test depends on that.
func TestAddr2Line(t *testing.T) {
	testenv.MustHaveGoBuild(t)

	tmpDir := t.TempDir()

			printed = f[0] + "\t" + strings.Join(f[1:], " ")
		}

		want := fmt.Sprintf("%05d (%s:%d)\t%s", seq, input, lineno, printed)
		for len(output) > 0 && (output[0] < want || output[0] != want && len(output[0]) >= 5 && output[0][:5] == want[:5]) {
			if len(output[0]) >= 5 && output[0][:5] == want[:5] {
				t.Errorf("mismatched output:\nhave %s\nwant %s", output[0], want)
				output = output[1:]
				continue Diff
			}

                is not available, instead of erroring out, the dependency result will
                be `None`.

                This is useful when you want to have optional authentication.

                It is also useful when you want to have authentication that can be
                provided in one of multiple optional ways (for example, with OAuth2
                or in a cookie).
                """

This means that you can send only the data that you want to update, leaving the rest intact.

/// note

`PATCH` is less commonly used and known than `PUT`.

And many teams use only `PUT`, even for partial updates.

You are **free** to use them however you want, **FastAPI** doesn't impose any restrictions.

But this guide shows you, more or less, how they are intended to be used.

		t.Log("Roundtrip:", time.Since(start))
		if len(resp) != 0 {
			t.Errorf("want nil, got %q", string(resp))
		}
		if err != RemoteErr(testPayload) {
			t.Errorf("want error %v(%T), got %v(%T)", RemoteErr(testPayload), RemoteErr(testPayload), err, err)
		}
		t.Log("Roundtrip:", time.Since(start))
	})

	t.Run("localToRemoteHuge", func(t *testing.T) {

		{"FALSE", false},
		{"\u0046alse", false},
	}

	for _, test := range checkTruthTests {
		t.Run(test.v, func(t *testing.T) {
			if out := CheckTruth(test.v); out != test.out {
				t.Errorf("CheckTruth(%s) want: %t, got: %t", test.v, test.out, out)
			}
		})
	}
}

func TestToStringKey(t *testing.T) {
	cases := []struct {
		values []interface{}
		key    string
	}{
		{[]interface{}{"a"}, "a"},

# OpenAPI Webhooks

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

## Webhooks steps

            description = "The extra gradle parameters you want to pass to this build, e.g. `-PrerunAllTests` or `--no-build-cache`"
        )
        text(
            "reverse.dep.*.additional.gradle.parameters",
            "",
            display = ParameterDisplay.NORMAL,
            allowEmpty = true,