Import('files_to_compile env')

language = files_to_compile[0].language
chapter = files_to_compile[0].chapter

from collections import defaultdict
chapter_files = defaultdict(list)

for file_info in files_to_compile:
    chapter_files[file_info.chapter].append(file_info.path)

for chapter, files in chapter_files.items():
    build_target = f'#/build/{language}/{chapter}/{chapter}'
    build_result = env.MCS(build_target, [str(file) for file in files])
    env.Alias(str(chapter), build_result)