def add_conditional(pConditional, pBehaviour = Languages::KEEP_LEVEL)
      return nil unless (pConditional.instance_of?Languages::ConditionalData)
      add_with_manager(pConditional, 'conditional', pBehaviour)
    end
def add_conditional(pConditional, pBehaviour = Languages::KEEP_LEVEL)
      return nil unless (pConditional.instance_of?Languages::ConditionalData)
      add_with_manager(pConditional, 'conditional', pBehaviour)
    end
Add conditional element inside function.
 @param pConditional An object of ConditionalData.
 @return If pConditional is not an instance of ConditionalData,
         return nil.