code: public boolean unmodifiedWithoutPhosphate() {
      if (getNotation() == null) {
        return true;
      } else {
        // System.out.println("Contains [ " + getNotation().contains("[") +
        // "\tContainsX " + getNotation().contains("["));
        if (getNotation().contains("[") || getNotation().contains("X")) {
          return false;
        } else {
          return true;
        }
      }
    }
docs: Returns true if the nucleotide is unmodified except for a missing phosphate
  group. If the nucleotide notation is empty, it returns true.
  
  @return true or false