public Builder addPlugins(final String engineName, final Map<String, Map<String,Object>> plugins) {
            this.plugins.put(engineName, plugins);
            return this;
        }
Add a configuration for a {@link GremlinPlugin} to the executor. The key is the fully qualified class name
of the {@link GremlinPlugin} instance and the value is a map of configuration values. In that map, the key
is the name of a builder method on the {@link GremlinPlugin} and the value is some argument to pass to that
method.
gremlin-groovy/src/main/java/org/apache/tinkerpop/gremlin/groovy/engine/GremlinExecutor.java