def METHOD_NAME(self):
    """Return the **binary** (non-printable) digest of the message that has been hashed so far.
    :return: The hash digest, computed over the data processed so far.
             Binary form.
    :rtype: byte string
    """
    bfr = create_string_buffer(self.digest_size)
    result = _raw_sha1_lib.SHA1_digest(self._state.get(),
                                       bfr)
    if result:
        raise ValueError("Error %d while instantiating SHA1"
                         % result)
    return get_raw_buffer(bfr)