IF statement in business process diagram

Hi everyone

I am new to the bpl diagram. I would like to add an if statement that checks whatever an object is null or not.

I guess that: condition='response.Content != null' would not be ok...

<if name='CheckObj' condition='response.Content != null' xpos='200' ypos='1700' xend='277' yend='2197' >

I tried to search for this information in the documentation but I didn't find any help.

Do you have any suggestions?

Thanks and best regards

Milena