public static IllegalArgumentException memoryKeyCanNotBeEmpty() {
            return new IllegalArgumentException("Graph computer memory key can not be the empty string");
        }
The Admin interface is used by the {@link GraphComputer} to update the Memory.
The developer should never need to type-cast the provided Memory to Memory.Admin.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/Memory.java