public String expectOneOf(Collection<String> validValues) {
        if (!validValues.contains(value)) {
            throw new ExpectationNotMetException(String.format(
                    "Expected one of %s; got `%s`.",
                    ValidationUtils.tickedList(validValues),
                    value), this);
        }
        return value;
    }
Gets the string if it is one of the provided valid strings.

@param validValues A list of valid string values.
@return The string value.
@throws ExpectationNotMetException if the value is not in the list.
smithy-model/src/main/java/software/amazon/smithy/model/node/StringNode.java