def find_importable_files(project: Project) -> Iterable[tuple[str, Path]]:
    """Find all possible files that can be imported"""
    from pdm.formats import FORMATS

    for filename in ("Pipfile", "pyproject.toml", "requirements.in", "requirements.txt", "setup.py", "setup.cfg"):
        project_file = project.root / filename
        if not project_file.exists():
            continue
        for key, module in FORMATS.items():
            if module.check_fingerprint(project, project_file.as_posix()):
                yield key, project_file
Find all possible files that can be imported
src/pdm/cli/utils.py