code: public Elements getElementsByAttributeStarting(String keyPrefix) {
          Validate.notEmpty(keyPrefix);
          keyPrefix = keyPrefix.trim();
  
          return Collector.collect(new Evaluator.AttributeStarting(keyPrefix), this);
      }
docs: Find elements that have an attribute name starting with the supplied prefix. Use {@code data-} to find elements
  that have HTML5 datasets.
  @param keyPrefix name prefix of the attribute e.g. {@code data-}
  @return elements that have attribute names that start with with the prefix, empty if none.