def can_sign(self, tx: 'Transaction', *, ignore_watching_only=False) -> bool:
        """Returns whether this keystore could sign *something* in this tx."""
        if not ignore_watching_only and self.is_watching_only():
            return False
        if not isinstance(tx, PartialTransaction):
            return False
        return bool(self._get_tx_derivations(tx))
Returns whether this keystore could sign *something* in this tx.
electrum/keystore.py