def get_pubkey_derivation(self, pubkey: bytes,
                              txinout: Union['PartialTxInput', 'PartialTxOutput'],
                              *, only_der_suffix=True) \
            -> Union[Sequence[int], str, None]:
        """Returns either a derivation int-list if the pubkey can be HD derived from this keystore,
        the pubkey itself (hex) if the pubkey belongs to the keystore but not HD derived,
        or None if the pubkey is unrelated.
        """
        pass
Returns either a derivation int-list if the pubkey can be HD derived from this keystore,
        the pubkey itself (hex) if the pubkey belongs to the keystore but not HD derived,
        or None if the pubkey is unrelated.
        
electrum/keystore.py