clean.py

from utils import SalesforceUtility

username = 'joe.fusaro@ivanti.com'
password = 'myPassword'
token = 'mySecurityToken'

if __name__ == "__main__":
    sfdc = SalesforceUtility(username, password, token)
    client = sfdc.connection

    members = client.query(
        """SELECT Id, Historical_Responded_Date__c,
        Campaign.StartDate, Status
        FROM CampaignMember
        WHERE CampaignId='7011B000002R6LwQAK' AND
        Status='No Show' AND
        Historical_Responded_Date__c = NULL
        """)
    print("\n\n\nUpdating {} records\n\n\n".format(members['totalSize']))

    for member in members['records']:
        client.CampaignMember.update(
            member['Id'],
            {'Historical_Responded_Date__c':member['Campaign']['StartDate']}
        )
        print('Updated {}\n'.format(member['Id']))

    print('-'*10 + 'COMPLETE' + '-'*10)

utils.py

import csv
from simple_salesforce import Salesforce

# set sys encoding=utf8
import sys
reload(sys)
sys.setdefaultencoding('utf8')


class SalesforceUtility(object):

    def __init__(self, username, password, security_token):
        self.username = username
        self.password = password
        self.security_token = security_token
        self.connection = self.connect()

    def connect(self):
        return Salesforce(
            username=self.username,
            password=self.password,
            security_token=self.security_token
            )