code: public static <K,V> Level0BuildingMapOperator<Map<K,V>,K,V> onMapFor(final K key, final V value) {
          final Map<K,V> newTarget = new LinkedHashMap<K, V>();
          newTarget.put(key, value);
          return new Level0BuildingMapOperator<Map<K,V>,K,V>(ExecutionTarget.forOp(newTarget, Normalisation.MAP));
      }
docs: <p>
  Creates a map containing one entry with the specified key and value, and an <i>operation
  expression</i> on it. Also enables the addition of new entries to the map by means of the
  <tt>and(...)</tt> action.
  </p>
  
  @param key the key for the map's first entry
  @param value the value for the map's first entry
  @return an operator, ready for chaining