def read_requirement_files(files):
    pip_requirements = []
    session = pip_download.PipSession()
    for filename in files:
        if sh.isfile(filename):
            cache_key = "f:%s:%s" % (sh.abspth(filename), sh.getsize(filename))
            with REQUIREMENT_FILE_CACHE_LOCK:
                try:
                    reqs = REQUIREMENT_FILE_CACHE[cache_key]
                except __HOLE__:
                    reqs = tuple(pip_req.parse_requirements(filename,
                                                            session=session))
                    REQUIREMENT_FILE_CACHE[cache_key] = reqs
                pip_requirements.extend(reqs)
    return (pip_requirements,
            [req.req for req in pip_requirements])
dataset/ETHPy150Open openstack/anvil/anvil/packaging/helpers/pip_helper.py/read_requirement_files