human
Solve the following python programming problem given the following code:
def add_proposal(self, p, proto = None) : 
    assert isinstance (p, Proposal) 
    assert ((proto is None) or isinstance (proto, HDCProtocol)) 
    def check(valid) : 
        if (not valid) : 
            self.tracked_protocol_failures.append (InvalidProposalEvidence (None, p)) 
            log.warn ('invalid proposal', p = p) 
            raise InvalidProposalError () 
return True 
self.log ('cm.add_proposal', p = p) 
    if (p.height < self.height) : 
        self.log ('proposal from the past') 
        return 
if (not check ((self.contract.isvalidator (p.sender) and self.contract.isproposer (p)))) : 
        return 
self.ready_validators.add (p.sender) 
    if (not check (p.lockset.is_valid)) : 
        return 
if (not check (((p.lockset.height == p.height) or (p.round == 0)))) : 
        return 
if (not check ((((p.round - p.lockset.round) == 1) or (p.round == 0)))) : 
        return 
if (proto is not None) : 
        self.synchronizer.on_proposal (p, proto) 
for v in p.lockset : 
        self.add_vote (v) 
if isinstance (p, BlockProposal) : 
        if (not check ((p.block.number == p.height))) : 
            return 
if (not check ((p.lockset.has_noquorum or (p.round == 0)))) : 
            return 
if (p.height > self.height) : 
            self.log ('proposal from the future, not in sync', p = p) 
            return 
blk = self.chainservice.link_block (p.block) 
        if (not check (blk)) : 
            ls = self.heights [p.height].last_quorum_lockset 
            if (ls and (ls.has_quorum == p.blockhash)) : 
                raise ForkDetectedEvidence (proto, (self.head, p, ls)) 
                sys.exit (1) 
return 
p._mutable = True 
        p._cached_rlp = None 
        p.block = blk 
        self.log ('successfully linked block') 
        self.add_block_proposal (p) 
else : 
        assert isinstance (p, VotingInstruction) 
        assert ((p.lockset.round == (p.round - 1)) and (is_valid.height == p.lockset.height)) 
        assert (p.round > 0) 
        assert p.lockset.has_quorum_possible 
  ...

    
    

    Fix the buggy line: assert ((p.lockset.round == (p.round - 1)) and (is_valid.height == p.lockset.height))
assistant
#Here is Python code to fix the buggy line: assert ((p.

assert ((p.lockset.round == (p.round - 1)) and (p.height == p.lockset.height))