human
I wrote the below code

    bears = set(bears)
    dependency_tracker = DependencyTracker()
    grouping = group(bears, key=(lambda bear: (bear.section, bear.file_dict)))
    for ((section, file_dict), bears_per_section) in grouping:
        bears_per_section = list(bears_per_section)
        type_to_instance_map = {}
        for bear in bears_per_section:
            type_to_instance_map[bear] = bear
            type_to_instance_map[type(bear)] = bear
        def instantiate_and_track(prev_bear_type, next_bear_type):
            if (next_bear_type not in type_to_instance_map):
                type_to_instance_map[next_bear_type] = next_bear_type(section, file_dict)
            dependency_tracker.add(type_to_instance_map[next_bear_type], type_to_instance_map[prev_bear_type])
        traverse_graph(bears_per_section, (lambda bear: bear.BEAR_DEPS), instantiate_and_track)
    bears -= {bear for bear in bears if dependency_tracker.get_dependencies(bear)}
    for dependency in dependency_tracker.dependencies:
        if (not dependency_tracker.get_dependencies(dependency)):
            bears.add(dependency)
    return (dependency_tracker, bears)

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def initialize_dependencies(bears):