code: public static <T, K> MapReduceCommand<T, K> build(String map, String reduce, OutputType outputType, String collection,
                                                        Class<T> resultType, Class<K> keyType) {
          return new MapReduceCommand<T, K>(map, reduce, outputType, collection, resultType, keyType);
      }
docs: Build a map reduce command
  
  @param map        The map function
  @param reduce     The reduce function
  @param outputType The outputType
  @param collection The collection name, may be null if output type is INLINE
  @param resultType The type to deserialise the result to
  @param keyType    The type of the keys that are being reduced on
  @return The command