If you are using `response_model` with some type that doesn't include `None` but the function is returning `None`, it will now raise an internal server error, because you are returning invalid data that violates the contract in `response_model`. Before this release it would allow breaking that contract returning `None`.

For example, if you have an app like this:

```Python
from fastapi import FastAPI

  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *
   * <p><b>Note:</b> as the reference file evolves, we will modify this matcher to keep it up to
   * date.
   *

* Fix incorrectly propagated ResourceVersion in ListRequests returning 0 items. ([#64150](https://github.com/kubernetes/kubernetes/pull/64150), [@wojtek-t](https://github.com/wojtek-t))

   *
   * <p>When the weight of an entry is zero it will not be considered for size-based eviction
   * (though it still may be evicted by other means).
   *
   * <p><b>Important note:</b> Instead of returning this as a {@code CacheBuilder}
   * instance, this method returns {@code CacheBuilder<K1, V1>}. From this point on, either the
   * original reference or the returned reference may be used to complete configuration and build

    inappropriate.

 *  New: `HttpUrl.get(String)` is an alternative to `HttpUrl.parse(String)` that throws an exception
    when the URL is malformed instead of returning null. Use this to avoid checking for null in
    situations where the input is known to be well-formed. We've also added `MediaType.get(String)`
    which is an exception-throwing alternative to `MediaType.parse(String)`.

    TF_Operation* op;
    UseHelper(inputs, &op);
    return op;
  }

  // All the *Helper methods are used as a workaround for the restrictions that
  // one cannot call ASSERT_* methods in non-void-returning functions (when
  // exceptions are disabled during compilation)
  void UseHelper(const std::vector<TF_Output>& inputs, TF_Operation** op) {
    TF_OperationDescription* desc =

              // if checkTime, we want to check *after* acquiring the lock if refresh still needs
              // to be scheduled
              return null;
            }

            // continue returning old value while loading
            ++modCount;
            LoadingValueReference<K, V> loadingValueReference =
                new LoadingValueReference<>(valueReference);

			}
		}
	}

	modTime := opts.MTime
	if opts.MTime.IsZero() {
		modTime = UTCNow()
	}
	fvID := mustGetUUID()

	defer func() {
		// attempt a heal before returning if there are offline disks
		// for both del marker and permanent delete situations.
		for _, disk := range storageDisks {
			if disk != nil && disk.IsOnline() {
				continue
			}

found in the _cgo_export.h generated header, after any preambles
copied from the cgo input files. Functions with multiple
return values are mapped to functions returning a struct.

Not all Go types can be mapped to C types in a useful way.
Go struct types are not supported; use a C struct type.
Go array types are not supported; use a C pointer.

      throws NoSuchMethodException {
    Method getMethod = List.class.getMethod("get", int.class);
    Invokable<T, String> invokable =
        new TypeToken<T>(getClass()) {}.method(getMethod).returning(String.class);
    assertEquals(TypeToken.of(String.class), invokable.getReturnType());
  }

  public <T extends List<String>> void testMethod_parameterTypes() throws NoSuchMethodException {