code: public static <K, V> Map<K, V> asUnmodifiable(Map<K, V> self) {
          return Collections.unmodifiableMap(self);
      }
docs: Creates an unmodifiable view of a Map.
  
  @param self a Map
  @return an unmodifiable view of the Map
  @see java.util.Collections#unmodifiableMap(java.util.Map)
  @see #asUnmodifiable(java.util.List)
  @since 2.5.0