How do I implement IF in mulesoft

I want to make a decision in a Mulesoft flow, and have looked at the Choice Flow Control. My problem, is that I want to do something if the condition is true, and nothing if it is false, something like:

if (condition == true)
   do some work

or, in probably incorrect xml:

<choice doc:name="call a subflow if the test is true">
    <when expression="#[flowVars.someVariable == True]">
        <flow-ref name="doSomething" doc:name="do another thing"/>
    </when>
</choice>

no else clause, and no default flow. How is this implemented in a Mulesoft flow? I could cheat, and throw a logging call into a default flow, but I would prefer not to.