Method checkValue

output/java_guava/1.4.17/AbstractBiMap.java:85–88

Returns its input, or throws an exception if this is not a valid value.

(@Nullable V value)

   */

  @CanIgnoreReturnValue
  V checkValue(@Nullable V value) {
    return value;
  }

  /**
   * Specifies the delegate maps going in each direction. Called by the