code: public static <K,V> Map<K,V> minus(Map<K,V> self, Map removeMe) {
          final Map<K,V> ansMap = createSimilarMap(self);
          ansMap.putAll(self);
          if (removeMe != null && removeMe.size() > 0) {
              for (Map.Entry<K, V> e1 : self.entrySet()) {
                  for (Object e2 : removeMe.entrySet()) {
                      if (DefaultTypeTransformation.compareEqual(e1, e2)) {
                          ansMap.remove(e1.getKey());
                      }
                  }
              }
          }
          return ansMap;
      }
docs: Create a Map composed of the entries of the first map minus the
  entries of the given map.
  
  @param self     a map object
  @param removeMe the entries to remove from the map
  @return the resulting map
  @since 1.7.4