I am currently having an issue. Fees are destroying my gains, so I decided to learn how to use the reality modeling section in the documentation. I am trying to incorporate the given line:

self.Securities["IBM"].FeeModel = ConstantFeeModel(1.5)

yet with my selection of stocks replacing the "IBM" and the fee being 0. When I try this, my algorithm no longer will work correctly. What variable do I use to replace "IBM"? I have tried many and have had no luck, I guess I don't understand how to transfer this knowledge for one stock into a whole universe. Thank you for any help.