public void addMapReduceMemoryKey(final MapReduce mapReduce) {
        this.memoryComputeKeys.put(mapReduce.getMemoryKey(), MemoryComputeKey.of(mapReduce.getMemoryKey(), Operator.assign, false, false));
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/util/MapMemory.java