how to animate in XML code block

[KamalnathOSU]

I had the following content in slide that will animate line-3 in the xml code block. But the animation does not work ?
Can someone guide me to find out what wrong ?

# SDB parameters for solute-trapping

  ```xml {all|3} 
    <Alloy name="AlSi10Mg">
      <solvent name="Al"/>
      <primary_phase name="Fcc"/>
    </Alloy>