While Skylark is a Python subset, there are slight differences between Skylark/BUILD style vs. the Google Python conventions. For example (from the Skylark cookbook:

def macro(name, visibility=None):
  # Creating a native genrule.
  native.genrule(
      name = name,
      outs = [name + '.txt'],
      cmd = 'echo hello > $@',
      visibility = visibility,
  )

Rule invocations such as native.genrule() follow the BUILD style rather than the standard Python function call style.

I think it would be good to write a Skylark Style Guide that defines a convention for Skylark code and lists some best practices.