assertThat(expected).hasMessageThat().contains("connected");

    // adjacent below
    assertEquals(Range.closedOpen(4, 4), range.intersection(Range.closedOpen(2, 4)));

    // overlap below
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(2, 6)));

    // enclosed with same start
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(4, 6)));

                    Set.of() // errors
                    );

            UpgradeResult result2 = new UpgradeResult(
                    Set.of(pom1), // processed (overlap)
                    Set.of(pom1, pom2), // modified (overlap + new)
                    Set.of() // errors
                    );

            UpgradeResult merged = result1.merge(result2);

    assertThat(expected).hasMessageThat().contains("connected");

    // adjacent below
    assertEquals(Range.closedOpen(4, 4), range.intersection(Range.closedOpen(2, 4)));

    // overlap below
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(2, 6)));

    // enclosed with same start
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(4, 6)));

      TYPE_PRIORITY, TYPE_RST_STREAM, TYPE_GOAWAY, TYPE_WINDOW_UPDATE -> return BINARY[flags]
    }
    val result = if (flags < FLAGS.size) FLAGS[flags]!! else BINARY[flags]
    // Special case types that have overlap flag values.
    return when {
      type == TYPE_PUSH_PROMISE && flags and FLAG_END_PUSH_PROMISE != 0 -> {
        result.replace("HEADERS", "PUSH_PROMISE") // TODO: Avoid allocation.
      }

    validations:
      required: true

  - type: textarea
    id: orthogonality
    attributes:
      label: "Orthogonality: How does this change interact or overlap with existing features?"
      description: "Is the goal of this change a performance improvement? If so, what quantifiable improvement should we expect? How would we measure it?"
    validations:
      required: false

   * Overlapping ranges and empty ranges are forbidden, though adjacent ranges are permitted and
   * will be merged.
   *
   * @throws IllegalArgumentException if any ranges overlap or are empty
   * @since 21.0
   */
  public static <C extends Comparable<?>> ImmutableRangeSet<C> copyOf(Iterable<Range<C>> ranges) {
    return new ImmutableRangeSet.Builder<C>().addAll(ranges).build();
  }

Also, the best approach was to use already existing standards.

So, before even starting to code **FastAPI**, I spent several months studying the specs for OpenAPI, JSON Schema, OAuth2, etc. Understanding their relationship, overlap, and differences.

## Design { #design }

Then I spent some time designing the developer "API" I wanted to have as a user (as a developer using FastAPI).

        checkInvalidRange("[1.0,1.0)");
        checkInvalidRange("(1.0,1.0)");
        checkInvalidRange("[1.1,1.0]");
        checkInvalidRange("[1.0,1.2),1.3");
        // overlap
        checkInvalidRange("[1.0,1.2),(1.1,1.3]");
        // overlap
        checkInvalidRange("[1.1,1.3),(1.0,1.2]");
        // ordering
        checkInvalidRange("(1.1,1.2],[1.0,1.1)");
    }

    @Test

	}
	// Mask matches maskString, should get result
	if err := ps.Subscribe(Mask(1|2), ch2, doneCh, func(entry Maskable) bool { return true }); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	// Does NOT overlap maskString
	if err := ps.Subscribe(Mask(2), ch3, doneCh, func(entry Maskable) bool { return true }); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	val := maskString("hello")
	ps.Publish(val)

    /**
     * Returns an {@code ImmutableRangeMap} containing the associations previously added to this
     * builder.
     *
     * @throws IllegalArgumentException if any two ranges inserted into this builder overlap
     */
    public ImmutableRangeMap<K, V> build() {
      sort(entries, Range.<K>rangeLexOrdering().onKeys());
      ImmutableList.Builder<Range<K>> rangesBuilder = new ImmutableList.Builder<>(entries.size());