def is_bin_file(filename: str) -> bool:
    """
    Simple filter function, returns true if the passed filename is considered
    to be a bin file which needs to be considered for the purpose of creating
    a cache-key, but may be deleted after an initial build.

    bin files are hashed, and their hashes are kept in a small separete file
    for future use when building the cache key. So the hash is not lost, even if the binary
    file is deleted.

    Args:
        filename (str): File path as a string

    Returns:
        bool: Whether the filename is a binary file in the above sense
    """
    return filename.lower().endswith(".bin")
Simple filter function, returns true if the passed filename is considered
to be a bin file which needs to be considered for the purpose of creating
a cache-key, but may be deleted after an initial build.

bin files are hashed, and their hashes are kept in a small separete file
for future use when building the cache key. So the hash is not lost, even if the binary
file is deleted.

Args:
filename (str): File path as a string

Returns:
bool: Whether the filename is a binary file in the above sense
python/aitemplate/backend/build_cache_base.py