// to explicitly say that the ContentLength is zero is
		// to set the Body to nil. But turns out too much code
		// depends on NewRequest returning a non-nil Body,
		// so we use a well-known ReadCloser variable instead
		// and have the http package also treat that sentinel
		// variable to mean explicitly zero.
		if req.GetBody != nil && req.ContentLength == 0 {
			req.Body = http.NoBody

🐍 3️⃣.6️⃣ & 🔛 (✅ 🐍 3️⃣.1️⃣0️⃣) 👆 💪 ⚙️ `Union` 🆎 ⚪️➡️ `typing` & 🚮 🔘 ⬜ 🗜 💪 🆎 🚫.

🐍 3️⃣.1️⃣0️⃣ 📤 **🎛 ❕** 🌐❔ 👆 💪 🚮 💪 🆎 👽 <abbr title='also called "bitwise or operator", but that meaning is not relevant here'>⏸ ⏸ (`|`)</abbr>.

//// tab | 🐍 3️⃣.6️⃣ &amp; 🔛

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial008b.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ &amp; 🔛

def _running_from_pip_package():
  return any(
      _current_file_location.startswith(dir_) for dir_ in _site_packages_dirs)

if _running_from_pip_package():
  # TODO(gunan): Add sanity checks to loaded modules here.

  # Load first party dynamic kernels.
  _tf_dir = _os.path.dirname(_current_file_location)
  _kernel_dir = _os.path.join(_tf_dir, "core", "kernels")
  if _os.path.exists(_kernel_dir):

    private File createJavadocForClass(String path) {
        new File(docsRoot, "javadoc/${path}.html").tap {
            parentFile.mkdirs()
            createNewFile()
            text = "Generated javadoc HTML goes here"
        }
    }

    private GradleRunner run(String... args) {
        return GradleRunner.create()
            .withProjectDir(projectDir)
            .withPluginClasspath()

    suite.addTest(
        MapTestSuiteBuilder.using(
                new TestTypeToInstanceMapGenerator() {
                  // Other tests will verify what real, warning-free usage looks like
                  // but here we have to do some serious fudging
                  @Override
                  @SuppressWarnings({"unchecked", "rawtypes"})
                  public Map<TypeToken, Object> create(Object... elements) {

  <properties>
    <!--
    We could override this to change which version we run tests under.
    However, I think that our -Djava.security.manager=allow profile is based on the *Maven* JDK.
    If we want to use overrides here, we should change that profile to also be based on surefire.toolchain.version.
    -->
    <surefire.toolchain.version>${java.specification.version}</surefire.toolchain.version>

  <properties>
    <!--
    We could override this to change which version we run tests under.
    However, I think that our -Djava.security.manager=allow profile is based on the *Maven* JDK.
    If we want to use overrides here, we should change that profile to also be based on surefire.toolchain.version.
    -->
    <surefire.toolchain.version>${java.specification.version}</surefire.toolchain.version>

```

////

And all of them can use `yield`.

In this case `dependency_c`, to execute its exit code, needs the value from `dependency_b` (here named `dep_b`) to still be available.

And, in turn, `dependency_b` needs the value from `dependency_a` (here named `dep_a`) to be available for its exit code.

//// tab | Python 3.9+

```Python hl_lines="18-19  26-27"

// error returned when more than a single policy is specified when only one is
// expected.
var errTooManyPolicies = errors.New("Only a single policy may be specified here.")

// error returned in IAM subsystem when an external users systems is configured.
var errIAMActionNotAllowed = errors.New("Specified IAM action is not allowed")

// error returned in IAM service account

                        new ProblemDetectingValueSource(prefixlessObjectBasedValueSource, "", PREFIX_PROJECT, problems);
            }
        }

        // NOTE: Order counts here!
        List<ValueSource> valueSources = new ArrayList<>(9);

        if (projectDir != null) {
            ValueSource basedirValueSource = new PrefixedValueSourceWrapper(