*/
  public static char toUpperCase(char c) {
    return isLowerCase(c) ? (char) (c ^ CASE_MASK) : c;
  }

  /**
   * Indicates whether {@code c} is one of the twenty-six lowercase ASCII alphabetic characters
   * between {@code 'a'} and {@code 'z'} inclusive. All others (including non-ASCII characters)
   * return {@code false}.
   */
  public static boolean isLowerCase(char c) {

    i = map.keySet().iterator();
    i.next();
    i.remove();
    assertNotified(listener, four, five, RemovalCause.EXPLICIT);

    map.put(five, six);
    i = map.values().iterator();
    i.next();
    i.remove();
    assertNotified(listener, five, six, RemovalCause.EXPLICIT);

    assertTrue(listener.isEmpty());
  }

  public void testRemovalListener_replaced() {

    i = map.keySet().iterator();
    i.next();
    i.remove();
    assertNotified(listener, four, five, RemovalCause.EXPLICIT);

    map.put(five, six);
    i = map.values().iterator();
    i.next();
    i.remove();
    assertNotified(listener, five, six, RemovalCause.EXPLICIT);

    assertTrue(listener.isEmpty());
  }

  public void testRemovalListener_replaced() {

   */
  public static char toUpperCase(char c) {
    return isLowerCase(c) ? (char) (c ^ CASE_MASK) : c;
  }

  /**
   * Indicates whether {@code c} is one of the twenty-six lowercase ASCII alphabetic characters
   * between {@code 'a'} and {@code 'z'} inclusive. All others (including non-ASCII characters)
   * return {@code false}.
   */
  public static boolean isLowerCase(char c) {

    --hash=sha256:e1f97cd89c0fe1a0685f8f89d85fa305deb3067d0668151571ba50913e445820
    # via
    #   -r ci/official/requirements_updater/requirements.in
    #   jax
six==1.16.0 \
    --hash=sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926 \
    --hash=sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254
    # via
    #   astunparse

    --hash=sha256:e1f97cd89c0fe1a0685f8f89d85fa305deb3067d0668151571ba50913e445820
    # via
    #   -r ci/official/requirements_updater/requirements.in
    #   jax
six==1.16.0 \
    --hash=sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926 \
    --hash=sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254
    # via
    #   astunparse

    --hash=sha256:f26264b282b9da0952a024ae34710c2aff7d27480ee91a2e82b7b7073c24722f
    # via
    #   -r ci/official/requirements_updater/requirements.in
    #   jax
six==1.16.0 \
    --hash=sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926 \
    --hash=sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254
    # via
    #   astunparse

    --hash=sha256:f26264b282b9da0952a024ae34710c2aff7d27480ee91a2e82b7b7073c24722f
    # via
    #   -r ci/official/requirements_updater/requirements.in
    #   jax
six==1.16.0 \
    --hash=sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926 \
    --hash=sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254
    # via
    #   astunparse

   *
   * <pre>{@code
   * Lists.cartesianProduct(ImmutableList.of(
   *     ImmutableList.of(1, 2),
   *     ImmutableList.of("A", "B", "C")))
   * }</pre>
   *
   * <p>returns a list containing six lists in the following order:
   *
   * <ul>
   *   <li>{@code ImmutableList.of(1, "A")}
   *   <li>{@code ImmutableList.of(1, "B")}
   *   <li>{@code ImmutableList.of(1, "C")}

    --hash=sha256:e1f97cd89c0fe1a0685f8f89d85fa305deb3067d0668151571ba50913e445820
    # via
    #   -r ci/official/requirements_updater/requirements.in
    #   jax
six==1.16.0 \
    --hash=sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926 \
    --hash=sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254
    # via
    #   astunparse