code: public static void argument(Boolean valid, Supplier<String> message) {
      if (isNotValid(valid)) {
        throw new IllegalArgumentException(message.get());
      }
    }
docs: Asserts that an argument is valid.
  
  The assertion holds if and only if {@code valid} is {@literal true}.
  
  For example, application code might assert that:
  
  <pre>
  <code>
  Assert.argument(age &gt;= 21, "Person must be 21 years of age to enter");
  </code>
  </pre>
  
  @param valid {@link Boolean} value resulting from the evaluation of the criteria used by the application
  to determine the validity of the argument.
  @param message {@link Supplier} containing the message for the {@link IllegalArgumentException} thrown
  if the assertion fails.
  @throws java.lang.IllegalArgumentException if the argument is invalid.
  @see java.util.function.Supplier