Identify undeliverable messages in Outlook

message_finder.py

import re
import win32com.client as client

# pattern for identifying email addresses
pattern = re.compile(r'mailto:(\w+\.\w+@company.com)')

outlook = client.Dispatch('Outlook.Application')
namespace = outlook.GetNameSpace('MAPI')
inbox = namespace.Folders['Inbox']

# extract all report type items that related to undelivered mail
returned = []

for item in inbox.Items:
  if item.Class == 46 and item.Subject.startswith('Undeliverable'):
    addresses = re.findall(pattern, item.Body)
    if addresses:
      returned.extend(addresses)
     
# unique addresses to remove from distribution
to_remove = list(set(returned))