code: public static <K,V> Map<K,V> asImmutable(Map<? extends K, ? extends V> self) {
          return Collections.unmodifiableMap(self);
      }
docs: A convenience method for creating an immutable map.
  
  @param self a Map
  @return an immutable Map
  @see java.util.Collections#unmodifiableMap(java.util.Map)
  @since 1.0