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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def verify_file(path, sha256):
 """ Verify the integrity of a file by checking its SHA-256 hash. If no digest is supplied, the digest is printed to the console. Closely follows the code in `torchvision.datasets.utils.check_integrity` Parameters path: str The path of the file to check sha256: str The expected SHA-256 hex digest of the file, or `None` to print the digest of the file to the console Returns ------- bool Indicates if the file passes the integrity check or not """

    if not os.path.isfile(path):
        return False
    digest = compute_sha256(path)
    if sha256 is None:
        # No digest supplied; report it to the console so a develop can fill
        # it in
        print('SHA-256 of {}:'.format(path))
        print('  "{}"'.format(digest))
    else:
        if digest != sha256:
            return False
    return True