code: public StringClauses getSubclause(String exitingKey) {
          exitingKey = StringUtil.trimToEmpty(exitingKey).toLowerCase();
          Object clauses = getImpl(exitingKey);
          if (clauses == null) {
              return null;
          }
          if (clauses instanceof String) {
              return new StringClauses().append((String) clauses);
          }
          return (StringClauses) clauses;
      }
docs: Retrieves the given key. Returns null if not set. If clause at key is a String, return a new StringClause version of it. Will traverse sub-clauses to find the key.