Jump to next empty column with Google Sheets & Python

I have a series of python scripts that enter data into a Google sheets column. I want to jump over to the next empty column if I run everything the next day. Here’s a simple version of what I’ve got - it just puts today’s date into cell A1.

import gspread
from oauth2client.service_account import ServiceAccountCredentials

scope = ['https://spreadsheets.google.com/feeds', 'https://www.googleapis.com/auth/drive']
creds = ServiceAccountCredentials.from_json_keyfile_name('client_penny.json', scope)
client = gspread.authorize(creds)

from datetime import datetime

date = datetime.today().strftime('%Y-%m-%d')

penny = client.open('pennystocks').worksheet('DGTW')

penny.update_acell('A1', date)

I want the date to go into B1 if I run it tomorrow (or whatever the next available column is if I’ve already run it a few times). I found these related examples, but I think they’re for javascript. (I’m a noon at this)