10 def packages(features, d):  argument
11     for feature in features:
16 def required_packages(features, d):  argument
17     req = [feature for feature in features if not is_optional(feature, d)]
20 def optional_packages(features, d):  argument
21     opt = [feature for feature in features if is_optional(feature, d)]
24 def active_packages(features, d):  argument
25     return itertools.chain(required_packages(features, d),
26                            optional_packages(features, d))
28 def active_recipes(features, d):  argument
31     for pkg in active_packages(features, d):