code: public static void isTrue(Boolean condition, Supplier<String> message) {
      if (isNotTrue(condition)) {
        throw new IllegalArgumentException(message.get());
      }
    }
docs: Asserts that the condition is {@literal true}.
  
  The assertion holds if and only if the value is equal to {@literal true}.
  
  @param condition {@link Boolean} value being evaluated as a {@literal true} condition.
  @param message {@link String} containing the message used in the {@link IllegalArgumentException} thrown
  if the assertion fails.
  @throws java.lang.IllegalArgumentException if the value is not {@literal true}.
  @see java.lang.Boolean#TRUE