code: private static BooleanNode doesStringContain(JsonNode subject, JsonNode search) {
          if (subject.asText().contains(search.asText())) {
              return BooleanNode.TRUE;
          }
          return BooleanNode.FALSE;
      }
docs: If the provided subject is a string, this function returns
  true if the string contains the provided search argument.
  
  @param subject String
  @param search  JmesPath expression
  @return True string contains search;
  False otherwise