code: @SuppressFBWarnings(justification = "Accepting that this is a bad practice - used a Boolean as we needed three states",
              value = {"NP_BOOLEAN_RETURN_NULL"})
      public Boolean getBooleanArgument(String argument) {
          if (line != null && line.hasOption(argument)) {
              final String value = line.getOptionValue(argument);
              if (value != null) {
                  return Boolean.parseBoolean(value);
              }
          }
          return null;
      }
docs: Returns the argument boolean value.
  
  @param argument the argument
  @return the argument boolean value