code: public Val nextKeyValue(String expectedKey) throws IOException {
        Tuple2<String, Val> Tuple2 = nextKeyValue();
        if (expectedKey != null && (Tuple2 == null || !Tuple2.getKey().equals(expectedKey))) {
           throw new IOException("Expected a Key-Value Tuple2 with named " + expectedKey);
        }
        return Tuple2.getV2();
     }
docs: Reads in a key value with an expected key.
  
  @param expectedKey The expected key
  @return The next key value Tuple2
  @throws IOException Something went wrong reading