Following CircleCI example, getting pycodestyle error

I am trying to follow the CircleCI example here:

It tries to run pycodestyle as part of the “build” step but I am getting error saying this command does not exist.

Also, in contrast with all of the examples for the other CI tools, for CircleCI, the docker build part is in the deploy step – not in the build step. Wondering why that choice was made for circle CI?