public static boolean isTransientVertexComputeKey(final String key, final Set<VertexComputeKey> vertexComputeKeySet) {
        for (final VertexComputeKey vertexComputeKey : vertexComputeKeySet) {
            if (vertexComputeKey.getKey().equals(key))
                return vertexComputeKey.isTransient();
        }
        throw new IllegalArgumentException("Could not find key in vertex compute key set: " + key);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/util/VertexProgramHelper.java