CAI check current message or memory field is numeric

Hello,

I am working on a bot that should create a purchase requisition.

I have several entities that are numeric. For example, plant is a four digit number or G/L account - a six digit number. When the user is asked for quantity, he enters a number. Normally it should be recognized as #number and can be processed further.

Sometimes this number is recognized as a plant or account.

In this case I wanted to save the current message in fallback-skill as quantity. I just need to check that the entry is numeric.

How can I check if the current message or a memory field is numeric?

Best regards and thanks in advance!

Alicja