def _filehash(filepath, blocksize=4096):
    """ Return the hash object for the file `filepath', processing the file
    by chunk of `blocksize'.

    :type filepath: str
    :param filepath: Path to file

    :type blocksize: int
    :param blocksize: Size of the chunk when processing the file

    """
    sha = hashlib.sha256()
    with open(filepath, 'rb') as fp:
        while 1:
            data = fp.read(blocksize)
            if data:
                sha.update(data)
            else:
                break
    return sha
Return the hash object for the file `filepath', processing the file
    by chunk of `blocksize'.

    :type filepath: str
    :param filepath: Path to file

    :type blocksize: int
    :param blocksize: Size of the chunk when processing the file