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