def get_payment_mpp_amount_msat(self, payment_hash: bytes) -> Optional[int]:
        """Returns the received mpp amount for given payment hash."""
        payment_key = self._get_payment_key(payment_hash)
        amounts = self.get_mpp_amounts(payment_key)
        if not amounts:
            return None
        total_msat, _ = amounts
        return total_msat
Returns the received mpp amount for given payment hash.
electrum/lnworker.py