Raspberry pi script AttributeError: module 'datetime' has no attribute 'now'

I'm getting this error when trying to run a script on my pi. I try to import datetime but then that errors too. Am i missing a indent or another function?

2020-07-20 13:26:56 - [INFO] doorbell: Listening for codes on GPIO 27
Connected with result code 0 12 384450 
Taking photo 

Traceback (most recent call last): 
    File "doorbell.py", line 79, in <module> 
        post_image()  
    File "doorbell.py", line 20, in post_image
        file_name ='image_' + str(datetime.now()) + '.jpg'  
AttributeError: module 'datetime' has no attribute 'now'

I've rang the script by going sudo nohup python3 doorbell.py this is the script.

# combine the MQTT and RF receive codes 
import paho.mqtt.client as mqtt 
import paho.mqtt.publish as publish 
import picamera 
import argparse 
import signal 
import sys 
import time 
import datetime
import logging 
from rpi_rf import RFDevice 
rfdevice = None 
### camera 
camera = picamera.PiCamera() 
camera.vflip=True 
#
def post_image(): 
   print('Taking photo') 
   camera.capture('image.jpg') 
   file_name = 'image_' + str(datetime.now()) + '.jpg' 
   camera.capture(file_name)  # time-stamped image 
   with open('image.jpg', "rb") as imageFile: 
       myFile = imageFile.read() 
       data = bytearray(myFile) 
   client.publish('dev/camera', data, mqttQos, mqttRetained)  # 
   client.publish('dev/test', 'Capture!')  # to trigger an automation later
   print(file_name + 'image published') 
#
### MQTT 
broker = '192.168.1.15' 
topic ='dev/test' 
mqttQos = 0 
mqttRetained = False 
#
def on_connect(client, userdata, flags, rc): 
   print("Connected with result code "+str(rc)) 
   client.subscribe(topic) 
# The callback for when a PUBLISH message is received from the server.
# 
def on_message(client, userdata, msg): 
   payload = str(msg.payload.decode('ascii'))  # decode the binary string 
   print(msg.topic + " " + payload) 
   process_trigger(payload) 
#
def process_trigger(payload): 
   if payload == 'ON': 
       print('ON triggered') 
       post_image() 
#
client = mqtt.Client() 
client.on_connect = on_connect    # call these on connect and on message 
client.on_message = on_message 
client.username_pw_set(username='',password='')  # need this 
client.connect(broker) 
client.loop_start()    #  run in background and free up main thread 
### RF 
#
def exithandler(signal, frame): 
   rfdevice.cleanup() 
   sys.exit(0) 
logging.basicConfig(level=logging.INFO, datefmt='%Y-%m-%d %H:%M:%S', 
                   format='%(asctime)-15s - [%(levelname)s] %(module)s: %(message)s', ) 
parser = argparse.ArgumentParser(description='Receives a decimal code via a 433/315MHz GPIO device') 
parser.add_argument('-g', dest='gpio', type=int, default=27, 
                   help="GPIO pin (Default: 27)") 
args = parser.parse_args() 
signal.signal(signal.SIGINT, exithandler) 
rfdevice = RFDevice(args.gpio) 
rfdevice.enable_rx() 
timestamp = None 
logging.info("Listening for codes on GPIO " + str(args.gpio)) 
code_of_interest = '384450' 
#
while True: 
   if rfdevice.rx_code_timestamp != timestamp: 
       timestamp = rfdevice.rx_code_timestamp 
       print(str(rfdevice.rx_code)) 
       if str(rfdevice.rx_code) == code_of_interest: 
           post_image() 
           time.sleep(1)  # prevent registering multiple times
   time.sleep(0.01) 
rfdevice.cleanup() 

Any help to solve this would be fantastic please. I'm trying to follow a doorbell that works when it gets the rf code running over home assistant. I can manually run the scripts from HA, when i run the script it errors on the above.

I've been trying to figure this out for a week now but I can't figure it out. my coding is not great but I can do basic python.

Thank you.

Try changing this:

def post_image(): 
   print('Taking photo') 
   camera.capture('image.jpg') 
   file_name = 'image_' + str(datetime.now()) + '.jpg' 
   camera.capture(file_name)  # time-stamped image 
   with open('image.jpg', "rb") as imageFile: 
       myFile = imageFile.read() 
       data = bytearray(myFile) 
   client.publish('dev/camera', data, mqttQos, mqttRetained)  # 
   client.publish('dev/test', 'Capture!')  # to trigger an automation later
   print(file_name + 'image published') 

into this:

def post_image(): 
   print('Taking photo') 
   camera.capture('image.jpg') 
   file_name = 'image_' + str(datetime.datetime.now()) + '.jpg' 
   camera.capture(file_name)  # time-stamped image 
   with open('image.jpg', "rb") as imageFile: 
       myFile = imageFile.read() 
       data = bytearray(myFile) 
   client.publish('dev/camera', data, mqttQos, mqttRetained)  # 
   client.publish('dev/test', 'Capture!')  # to trigger an automation later
   print(file_name + 'image published')