code: public ComparatorCondition ne(String... values) {
          return new ComparatorCondition("<>", this, new LiteralOperand(
                  new LinkedHashSet<String>(Arrays.asList(values))));
      }
docs: Returns a <a href=
  "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
  >comparator condition</a> (that evaluates to true if the value of the
  current attribute is not equal to the set of specified values) for
  building condition expression.