return
	}

	action := r.Form.Get(stsAction)
	switch action {
	case assumeRole:
	default:
		writeSTSErrorResponse(ctx, w, ErrSTSInvalidParameterValue, fmt.Errorf("Unsupported action %s", action))
		return
	}

	ctx = newContext(r, w, action)

	// Validate the authentication result here so that failures will be audit-logged.
	if apiErrCode != ErrNone {

	// Validate format version and format type.
	if formatErasure.Version != formatMetaVersionV1 {
		return fmt.Errorf("Unsupported version of backend format [%s] found on %s", formatErasure.Version, disk)
	}
	if formatErasure.Format != formatBackendErasure && formatErasure.Format != formatBackendErasureSingle {
		return fmt.Errorf("Unsupported backend format [%s] found on %s", formatErasure.Format, disk)
	}

    return invertedMultimap;
  }

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public final ImmutableList<V> removeAll(@CheckForNull Object key) {

    }
  }

  ImmutableMap() {}

  /**
   * Guaranteed to throw an exception and leave the map unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  @CheckForNull
  public final V put(K k, V v) {

type NotImplemented struct {
	Message string
}

func (e NotImplemented) Error() string {
	return e.Message
}

// UnsupportedMetadata - unsupported metadata
type UnsupportedMetadata struct{}

func (e UnsupportedMetadata) Error() string {
	return "Unsupported headers in Metadata"
}

// isErrBucketNotFound - Check if error type is BucketNotFound.
func isErrBucketNotFound(err error) bool {

      return set;
    }

    /**
     * Guaranteed to throw an exception and leave the collection unmodified.
     *
     * @throws UnsupportedOperationException always
     * @deprecated Unsupported operation.
     */
    @CanIgnoreReturnValue
    @Deprecated
    @Override
    @DoNotCall("Always throws UnsupportedOperationException")
    public final boolean add(@ParametricNullness E e) {

  }

  /**
   * {@inheritDoc}
   *
   * <p>This implementation is guaranteed to throw an {@link UnsupportedOperationException}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  @CheckForNull
  public final Entry<E> pollFirstEntry() {

    return invertedMultimap;
  }

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public final ImmutableSet<V> removeAll(@CheckForNull Object key) {

  public static <K, V> ImmutableSortedMap.Builder<K, V> builder() {
    throw new UnsupportedOperationException();
  }

  /**
   * Not supported for ImmutableSortedMap.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Not supported for ImmutableSortedMap.
   */
  @DoNotCall("Use naturalOrder (which does not accept an expected size)")
  @Deprecated

    throw new UnsupportedOperationException();
  }

  /**
   * Not supported. This method exists only to hide {@link ImmutableSet#builderWithExpectedSize}
   * from consumers of {@code ImmutableSortedSet}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Not supported by ImmutableSortedSet.
   */
  @DoNotCall("Use naturalOrder (which does not accept an expected size)")