code: private TimeUnit getPollUnit() {
      String unit = mProperties.getProperty(CSV_KEY_UNIT);
      if (unit == null) {
        unit = CSV_DEFAULT_UNIT;
      }
      return TimeUnit.valueOf(unit.toUpperCase());
    }
docs: Gets the polling time unit.
  
  @return the polling time unit set by properties, If it is not set, a default value SECONDS is
  returned.