[Python] How to skip data already imported using Python

I am importing data from a csv file into a database using an API. I've already run the script below and a little less than half of the data was imported. Something caused the API to stop and now I am looking to run the script again. I've tested a few lines from the csv file and data that has already been imported is being duplicated. Is there a way to modify the script so that imported data is skipped? I was thinking some type of if statement, but I am not quite sure. Any suggestions?

def opencsv():
'''This function opens a csv file'''
input_csv = 'agentlinks.csv'
file = open(input_csv, 'r')
csvin = csv.reader(file)
#Skip header row
next(csvin, None)
return csvin

def addUriLink():
"""Add URI link to record."""
api_url, headers = as_login.login()
csvfile = opencsv()
for row in csvfile:
repo_id = row[1]
resource_id = row[2]
value = row[3]
resource_uri='repositories/' + repo_id + '/resources/' + str(resource_id)
resource_json = requests.get(api_url + '/repositories/' + repo_id + '/resources/' + str(resource_id), headers=headers).json()
updatedRecord = resource_json
agents = updatedRecord['linked_agents']
agent = {}
agent['ref'] = value
agent['role'] = 'subject'
if agent not in agents:
agents.append(agent)
updatedRecord['linked_agents'] = agents
print(updatedRecord['linked_agents'])
updatedRecord = json.dumps(updatedRecord)
print(api_url + resource_uri)
post = requests.post(api_url + '/repositories/' + repo_id + '/resources/' + str(resource_id), headers=headers, data=updatedRecord).json()
print(post)
else:
print('no update')
log = open("addAgentsLinks.txt", "a")
print(updatepost, file=log)
addUriLink()

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