code: public boolean directIsA(String hypoID, String hyperID) {
          if (!terms.containsKey(hypoID))
              return false;
          OntologyTerm term = terms.get(hypoID);
          if (term.getIsA().contains(hyperID))
              return true;
          return false;
      }
docs: Tests whether there is a direct is_a (or has_role) relationship between
  two IDs.
  
  @param hypoID
  The potential hyponym (child term).
  @param hyperID
  The potential hypernym (parent term).
  @return Whether that direct relationship exists.