def fingerprint(self, format=FingerprintFormats.MD5_HEX):
        """
        The fingerprint of a public key consists of the output of the
        message-digest algorithm in the specified format.
        Supported formats include L{FingerprintFormats.MD5_HEX} and
        L{FingerprintFormats.SHA256_BASE64}

        The input to the algorithm is the public key data as specified by [RFC4253].

        The output of sha256[RFC4634] algorithm is presented to the
        user in the form of base64 encoded sha256 hashes.
        Example: C{US5jTUa0kgX5ZxdqaGF0yGRu8EgKXHNmoT8jHKo1StM=}

        The output of the MD5[RFC1321](default) algorithm is presented to the user as
        a sequence of 16 octets printed as hexadecimal with lowercase letters
        and separated by colons.
        Example: C{c1:b1:30:29:d7:b8:de:6c:97:77:10:d7:46:41:63:87}

        @param format: Format for fingerprint generation. Consists
            hash function and representation format.
            Default is L{FingerprintFormats.MD5_HEX}

        @since: 8.2

        @return: the user presentation of this L{Key}'s fingerprint, as a
        string.

        @rtype: L{str}
        """
        if format is FingerprintFormats.SHA256_BASE64:
            return nativeString(base64.b64encode(
                sha256(self.blob()).digest()))
        elif format is FingerprintFormats.MD5_HEX:
            return nativeString(
                b':'.join([binascii.hexlify(x)
                           for x in iterbytes(md5(self.blob()).digest())]))
        else:
            raise BadFingerPrintFormat(
                'Unsupported fingerprint format: %s' % (format,))

        The fingerprint of a public key consists of the output of the
        message-digest algorithm in the specified format.
        Supported formats include L{FingerprintFormats.MD5_HEX} and
        L{FingerprintFormats.SHA256_BASE64}

        The input to the algorithm is the public key data as specified by [RFC4253].

        The output of sha256[RFC4634] algorithm is presented to the
        user in the form of base64 encoded sha256 hashes.
        Example: C{US5jTUa0kgX5ZxdqaGF0yGRu8EgKXHNmoT8jHKo1StM=}

        The output of the MD5[RFC1321](default) algorithm is presented to the user as
        a sequence of 16 octets printed as hexadecimal with lowercase letters
        and separated by colons.
        Example: C{c1:b1:30:29:d7:b8:de:6c:97:77:10:d7:46:41:63:87}

        @param format: Format for fingerprint generation. Consists
            hash function and representation format.
            Default is L{FingerprintFormats.MD5_HEX}

        @since: 8.2

        @return: the user presentation of this L{Key}'s fingerprint, as a
        string.

        @rtype: L{str}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/ssh/keys.py