Multiple conditions on single sequence flow

Hi, can we give multiple conditions on sequence flow. For ex: I tried this: ${variable1!='DEFAULT'}&${variable2!='DEFAULT'}, but this gave me error saying that result is String true&true. I tried using && also, got the same result.
Can we give multiple conditions on single sequence flow?
If yes, what’s the format of that?

i dont have modeler at hand to test it, but i guess it should be

${variable1!=‘DEFAULT’ && variable2!=‘DEFAULT’}

Yes, I found one link earlier. Forgot to mention it here