diff --git a/OEP64Sample/OEP64Sample.py b/OEP64Sample/OEP64Sample.py
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+"""
+An Example of OEP-64
+"""
+from ontology.interop.Ontology.Contract import Migrate
+from ontology.interop.System.Action import RegisterAction
+from ontology.interop.Ontology.Runtime import Base58ToAddress
+from ontology.interop.System.Storage import Get, GetContext, Put
+from ontology.builtins import sha256, concat
+from ontology.interop.System.Runtime import Serialize, Deserialize, Log, CheckWitness, GetTime, Notify
+
+# vote status
+STATUS_NOT_FOUND = 'not found'
+
+# pre + hash -> topic
+PRE_TOPIC = '01'
+# topic_info + hash -> topicInfo:[admin, topic_title, topic_detail, voter address,startTime, endTime, approve amount,
+# reject amount, status, topic hash]
+PRE_TOPIC_INFO = '02'
+
+# pre + hash -> voted address: [['address1', 1],['address2',2]]
+PRE_VOTED = '03'
+
+
+# key -> all topic hash
+KEY_ALL_TOPIC_HASH = 'all_hash'
+# key -> all admin
+KEY_ADMINS = 'all_admin'
+
+ctx = GetContext()
+SUPER_ADMIN = Base58ToAddress("AbtTQJYKfQxq4UdygDsbLVjE8uRrJ2H3tP")
+
+CreateTopicEvent = RegisterAction("createTopic", "hash", "topic_title", "topic_detail")
+VoteTopicEvent = RegisterAction("voteTopic", "hash", "voter")
+VoteTopicEndEvent = RegisterAction("voteTopicEnd", "hash", "voter")
+
+
+def Main(operation, args):
+    """
+    only super admin can invoke
+    """
+    if operation == 'init':
+        return init()
+    if operation == 'setAdmin':
+        Require(len(args) == 1)
+        admins = args[0]
+        return setAdmin(admins)
+    if operation == 'upgrade':
+        Require(len(args) == 7)
+        code = args[0]
+        needStorage = args[1]
+        name = args[2]
+        version = args[3]
+        author = args[4]
+        email = args[5]
+        desc = args[6]
+        return upgrade(code, needStorage, name, version, author, email, desc)
+    """
+    only admin can invoke
+    """
+    if operation == 'createTopic':
+        Require(len(args) == 6)
+        admin = args[0]
+        topic_title = args[1]
+        topic_detail = args[2]
+        start_time = args[3]
+        end_time = args[4]
+        voters = args[5]
+        return createTopic(admin, topic_title, topic_detail, start_time, end_time, voters)
+    if operation == 'cancelTopic':
+        Require(len(args) == 1)
+        hash = args[0]
+        return cancelTopic(hash)
+    if operation == 'setVoterForTopic':
+        Require(len(args) == 2)
+        hash = args[0]
+        voters = args[1]
+        return setVoterForTopic(hash, voters)
+    # all user can invoke
+    if operation == 'listAdmins':
+        return listAdmins()
+    if operation == 'listTopics':
+        Require(len(args) == 0)
+        return listTopics()
+    if operation == 'getTopic':
+        Require(len(args) == 1)
+        hash = args[0]
+        return getTopic(hash)
+    if operation == 'getTopicInfo':
+        Require(len(args) == 1)
+        hash = args[0]
+        return getTopicInfo(hash)
+    if operation == 'getVoters':
+        Require(len(args) == 1)
+        hash = args[0]
+        return getVoters(hash)
+    if operation == 'voteTopic':
+        Require(len(args) == 3)
+        hash = args[0]
+        voter = args[1]
+        approveOrReject = args[2]
+        return voteTopic(hash, voter, approveOrReject)
+    if operation == 'getVotedInfo':
+        Require(len(args) == 2)
+        hash = args[0]
+        addr = args[1]
+        return getVotedInfo(hash, addr)
+    if operation == 'getVotedAddress':
+        Require(len(args) == 1)
+        hash = args[0]
+        return getVotedAddress(hash)
+    if operation == "getTopicInfoListByAdmin":
+        Require(len(args) == 1)
+        admin = args[0]
+        return getTopicInfoListByAdmin(admin)
+    return False
+
+
+# ****only super admin can invoke*********
+def init():
+    RequireWitness(SUPER_ADMIN)
+    info = Get(ctx, KEY_ADMINS)
+    assert(info == None)
+    Put(ctx, KEY_ADMINS, Serialize([SUPER_ADMIN]))
+    return True
+
+
+# only SuperAdmin can invoke this method
+def setAdmin(admins):
+    RequireWitness(SUPER_ADMIN)
+    for admin in admins:
+        RequireIsAddress(admin)
+    Put(ctx, KEY_ADMINS, Serialize(admins))
+    return True
+
+
+# upgrade contract
+def upgrade(code, needStorage, name, version, author, email, desc):
+    RequireWitness(SUPER_ADMIN)
+    r = Migrate(code, needStorage, name, version, author, email, desc)
+    Require(r is True)
+    Notify(["Migrate successfully"])
+    return True
+
+
+# query all admins
+def listAdmins():
+    info = Get(ctx, KEY_ADMINS)
+    if info == None:
+        return []
+    return Deserialize(info)
+
+
+# ****only admin can invoke*********
+# [admin, topic_title, topic_detail, voter address,startTime, endTime, approve amount, reject amount, status,topic hash]
+# create a voting topic, only admin can invoke this method
+def createTopic(admin, topic_title, topic_detail, startTime, endTime, voters):
+    RequireWitness(admin)
+    Require(isAdmin(admin))
+    Require(startTime < endTime)
+    for voter in voters:
+        Require(len(voter) == 2)
+        RequireIsAddress(voter[0])
+    hash = sha256(concat(topic_title, topic_detail))
+    keyTopic = getKey(PRE_TOPIC, hash)
+    data = Get(ctx, keyTopic)
+    Require(data is None)
+    Put(ctx, keyTopic, Serialize([topic_title, topic_detail]))
+    keyTopicInfo = getKey(PRE_TOPIC_INFO, hash)
+    topicInfo = [admin, topic_title, topic_detail, voters, startTime, endTime, 0, 0, 1, hash]
+    Put(ctx, keyTopicInfo, Serialize(topicInfo))
+    hashs = []
+    bs = Get(ctx, KEY_ALL_TOPIC_HASH)
+    if bs:
+        hashs = Deserialize(bs)
+    hashs.append(hash)
+    Put(ctx, KEY_ALL_TOPIC_HASH, Serialize(hashs))
+    CreateTopicEvent(hash, topic_title, topic_detail)
+    return True
+
+def cancelTopic(hash):
+    topicInfo = getTopicInfo(hash)
+    Require(len(topicInfo) == 10)
+    Require(topicInfo[8] == 1)
+    RequireWitness(topicInfo[0])
+    topicInfo[8] = 0
+    key = getKey(PRE_TOPIC_INFO, hash)
+    Put(ctx, key, Serialize(topicInfo))
+    return True
+
+# set voters for topic, only these voter can vote, [[voter1, weight1],[voter2, weight2]]
+def setVoterForTopic(hash, voters):
+    Require(len(voters) != 0)
+    for voter in voters:
+        Require(len(voter) == 2)
+        RequireIsAddress(voter[0])
+    key = getKey(PRE_TOPIC_INFO, hash)
+    info = Get(ctx, key)
+    Require(info is not None)
+    topicInfo = Deserialize(info)
+    RequireWitness(topicInfo[0])
+    topicInfo[3] = voters
+    Put(ctx, key, Serialize(topicInfo))
+    return True
+
+
+# ****all user can invoke method ***********
+# query all topic hash
+def listTopics():
+    bs = Get(ctx, KEY_ALL_TOPIC_HASH)
+    if bs == None:
+        return []
+    else:
+        return Deserialize(bs)
+
+# query topicInfo by admin
+def getTopicInfoListByAdmin(admin):
+    hashs = listTopics()
+    res = []
+    for hash in hashs:
+        topicInfo = getTopicInfo(hash)
+        if topicInfo[0] == admin:
+            res.append(topicInfo)
+    return res
+
+# query topic title and topic detail by topic hash, [topic_title, topic_detail]
+def getTopic(hash):
+    key = getKey(PRE_TOPIC, hash)
+    info = Get(ctx, key)
+    if info is None:
+        return []
+    else:
+        return Deserialize(info)
+
+
+# query topicInfo including [admin, topic, voter address,startTime, endTime, approve amount, reject amount, state,
+# topic hash]
+def getTopicInfo(hash):
+    key = getKey(PRE_TOPIC_INFO, hash)
+    info = Get(ctx, key)
+    if info is None:
+        return []
+    return Deserialize(info)
+
+# query voters of the topic
+def getVoters(hash):
+    key = getKey(PRE_TOPIC_INFO, hash)
+    info = Get(ctx, key)
+    if info == None:
+        return []
+    topicInfo = Deserialize(info)
+    return topicInfo[3]
+
+
+# vote topic, only voter who authored by topic admin can invoke
+# [admin, topic_title, topic_detail, voter address,startTime, endTime, approve amount, reject amount, status,
+#  topic hash]
+def voteTopic(hash, voter, approveOrReject):
+    RequireWitness(voter)
+    if isValidVoter(hash, voter) is False:
+        Notify(["isValidVoter failed"])
+        return False
+    votedInfo = getVotedInfo(hash, voter)
+    if votedInfo == 1:
+        Require(approveOrReject is False)
+    if votedInfo == 2:
+        Require(approveOrReject is True)
+    topicInfo = getTopicInfo(hash)
+    if len(topicInfo) != 10:
+        Notify(["len(topicInfo) is wrong"])
+        return False
+    if topicInfo[8] != 1:
+        Notify(["canceled topic"])
+        return False
+    cur = GetTime()
+    if cur < topicInfo[4]:
+        Notify(["not start"])
+        return False
+    if cur >= topicInfo[5]:
+        Notify(["has end"])
+        return False
+    if approveOrReject:
+        topicInfo[6] += getVoterWeight(voter, hash)
+        if votedInfo == 2:
+            topicInfo[7] -= getVoterWeight(voter, hash)
+    else:
+        topicInfo[7] += getVoterWeight(voter, hash)
+        if votedInfo == 1:
+            topicInfo[6] -= getVoterWeight(voter, hash)
+    keyTopicInfo = getKey(PRE_TOPIC_INFO, hash)
+    Put(ctx, keyTopicInfo, Serialize(topicInfo))
+    updateVotedAddress(voter, hash, approveOrReject)
+    VoteTopicEvent(hash, voter)
+    return True
+
+# query the weight of voter
+def getVoterWeight(voter, hash):
+    voters = getVoters(hash)
+    for voter_item in voters:
+        if voter_item[0] == voter:
+            return voter_item[1]
+    return 0
+
+# 1: approve, 2: reject, other: not voted
+def getVotedInfo(hash, voter):
+    key = getKey(PRE_VOTED, hash)
+    info = Get(ctx, key)
+    if info == None:
+        return 0
+    votedInfos = Deserialize(info)
+    for votedInfo in votedInfos:
+        if votedInfo[0] == voter:
+            return votedInfo[1]
+    return 0
+
+def isValidVoter(hash, voter):
+    voters = getVoters(hash)
+    for addr in voters:
+        if addr[0] == voter:
+            return True
+    return False
+
+# [['Address', 1],['Address', 2]], 1. true 2. false
+def updateVotedAddress(voter, hash, approveOrReject):
+    key = getKey(PRE_VOTED, hash)
+    info = Get(ctx, key)
+    votedAddrs = []
+    if info != None:
+        votedAddrs = Deserialize(info)
+        for voteInfo in votedAddrs:
+            if voteInfo[0] == voter:
+                if approveOrReject:
+                    voteInfo[1] = 1
+                else:
+                    voteInfo[1] = 2
+                Put(ctx, key, Serialize(votedAddrs))
+                return True
+    if approveOrReject:
+        votedAddrs.append([voter, 1])
+    else:
+        votedAddrs.append([voter, 2])
+    Put(ctx, key, Serialize(votedAddrs))
+    return True
+
+def getVotedAddress(hash):
+    key = getKey(PRE_VOTED, hash)
+    info = Get(ctx, key)
+    votedAddrs = []
+    if info != None:
+        votedAddrs = Deserialize(info)
+    return votedAddrs
+
+def getKey(pre, hash):
+    '''
+    Gets the storage key for looking up a balance
+    :param address:
+    '''
+    key = concat(pre, hash)  # pylint: disable=E0602
+    return key
+
+def isAdmin(admin):
+    '''
+    need admin signature
+    '''
+    admins = listAdmins()
+    for item in admins:
+        if item == admin:
+            return True
+    return False
+
+def RequireWitness(address):
+    '''
+    Raises an exception if the given address is not a witness.
+    :param address: The address to check.
+    '''
+    Require(CheckWitness(address), "Address is not witness")
+
+
+def Require(expr, message="There was an error"):
+    '''
+    Raises an exception if the given expression is false.
+    :param expr: The expression to evaluate.
+    :param message: The error message to log.
+    '''
+    if not expr:
+        Log(message)
+        raise Exception(message)
+
+def RequireIsAddress(address):
+    '''
+    Raises an exception if the given address is not the correct length.
+    :param address: The address to check.
+    '''
+    Require(len(address) == 20, "Address has invalid length")
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