Generate an MD5 hash of the specified file.

    @file_name - The file to hash.

    Returns an MD5 hex digest string.

def file_md5(file_name):
    '''
    Generate an MD5 hash of the specified file.

    @file_name - The file to hash.

    Returns an MD5 hex digest string.
    '''
    md5 = hashlib.md5()

    with open(file_name, 'rb') as f:
        for chunk in iter(lambda: f.read(128 * md5.block_size), b''):
            md5.update(chunk)

    return md5.hexdigest()