The NameError is quite specific. It means that ‘pat_enc_hw’ does not represent anything, at this point in the Python script and as such the calculation to the right of the = can’t be carried out and then assigned to the object to the left of the =
(so far as I can tell, from the limited information).
How do I assign it to represent something
Above the # (7) box, I can just make out a Template: comment, which (I guess) is showing you how to build the pat_enc_hw object.
It seems it wants you to define pat_enc_hw in the previous cell # (6), where you firstly need to substitute ... with the correct stuff.