使用gspread获取逗号分隔的单元格值列表

Question

我想发送包含谷歌电子表格中存储的电子邮件地址的邮件。我能够获得单元格值，但我得到了：

(<Cell R1C1 'email@gmail.com'>,)
(<Cell R2C1 'email1@gmail.com'>,)
...

为了使用MIMEMultipart，我需要一个逗号分隔： 电子邮件@ gmail.com，email1gmail.com，...

这是我的代码：

import gspread
import json
from oauth2client.client import SignedJwtAssertionCredentials
import gdata.spreadsheet.service
from email.MIMEMultipart import MIMEMultipart
from email.MIMEText import MIMEText
import smtplib

json_key = json.load(open('xxx.json'))
scope = ['https://spreadsheets.google.com/feeds']
credentials = SignedJwtAssertionCredentials(json_key['client_email'], json_key['private_key'], scope)
gc = gspread.authorize(credentials)

wks = gc.open('xxx')
worksheet_id = 'od6'
worksheet = wks.get_worksheet(0)

print worksheet.row_values("A1")

for x in xrange(1,50):
test = "A%s" %x
msg = MIMEMultipart()
msg["To"] = worksheet.acell(test),
print msg["To"]