public String execute(List<String> parameterList, TestContext context) {
int numberLength;
boolean paddingOn = true;
if (CollectionUtils.isEmpty(parameterList)) {
throw new InvalidFunctionUsageException("Function parameters must not be empty");
}
if (parameterList.size() > 2) {
throw new InvalidFunctionUsageException("Too many parameters for function");
}
numberLength = Integer.valueOf(parameterList.get(0));
if (numberLength < 0) {
throw new InvalidFunctionUsageException("Invalid parameter definition. Number of letters must not be positive non-zero integer value");
}
if (parameterList.size() > 1) {
paddingOn = Boolean.valueOf(parameterList.get(1));
}