Print the number of processed parameter frames by group name.

def print_pp_groups():
    """Print the number of processed parameter frames by group name."""
    for group in archive.list_processed_parameter_groups():
        frame_count = 0
        for pp_group in archive.list_processed_parameter_group_histogram(group):
            for rec in pp_group.records:
                frame_count += rec.count
        print('  {: <40} {: >20}'.format(group, frame_count))