@Override
    public Attribute.Type getReturnType() {
        return Attribute.Type.OBJECT;
    }
Executor class for Siddhi event attribute that produces multiple values.
This executor is used to extract multiple attribute values as a list from
{@link ComplexEvent}.
modules/siddhi-core/src/main/java/io/siddhi/core/executor/MultiValueVariableFunctionExecutor.java