code: protected static Number maximum(List<?> slaveValues) {
          Number max = null;
          for (Object slaveValue : slaveValues) {
              if (max == null) {
                  max = (Number) slaveValue;
              } else {
                  Comparable<Object> comparable = NumberComparator.getComparable(max);
                  if (comparable.compareTo(slaveValue) < 0) {
                      max = (Number) slaveValue;
                  }
              }
          }
          return max;
      }
docs: Helper method to get the maximum of all values (must be numbers)
  
  @param slaveValues
  @return