Using the message body for calculations

Hey

I’m trying to use the body of a message in a python calculation.
I want to work with “dmg”
I’ve tried :
dmg = msg.getBodies()
bleh = dmg*blah+blah-blah/blah etc.

The console returns with this error:
TypeError: unsupported operand type<s> for *:‘CListValue’ and ‘int’

Can anyone tell me how I should be doing it?
Thanks

int(body)

assuming it is a string

or

float(body)

[same assumption]