def get_simple_multisig(self) -> Optional['MultisigDescriptor']:
        """Returns innermost multi descriptor, or None if we are not a simple multisig."""
        if len(self.subdescriptors) == 1:
            return self.subdescriptors[0].get_simple_multisig()
        return None
Returns innermost multi descriptor, or None if we are not a simple multisig.
electrum/descriptor.py