code: public Collection<BeanType> get(String key, Object value) {
          IndexType index = indexMap.get(key);
          
          if (index == null) {
              throw new BitsyException(BitsyErrorCodes.MISSING_INDEX, "An index on " + key + " must be created before querying vertices/edges by that key. Defined indexes: " + indexMap.keySet());
          } else {
              return index.get(value);
          }
      }
docs: This method returns a copy of the edges/vertices held for the given key and value