Problem with python logging.handlers.SMTPHandler, 'credentials' not recognized as attribute of SMTPHandler

I’m trying to set up email logging of critical errors in my python application. I keep running into an error trying to initialize the SMTPHandler:

AttributeError: ‘SMTPHandler’ object has no attribute ‘credentials’

I’m using Python 3.10. I carved out a component of the program where I’m getting the error.

import logging
from logging.handlers import SMTPHandler

mail_handler = SMTPHandler(
    mailhost='my.hosting.com',
    fromaddr='admin@myapp.com',
    toaddrs=['admin@myapp.com'],
    subject='Application Error', 
    credentials=('admin@myapp.com', 'mypassword'),
    secure=()
)
print(mail_handler.mailhost)
print(mail_handler.fromaddr)
print(mail_handler.toaddrs)
print(mail_handler.subject)
print(mail_handler.secure)
print(mail_handler.timeout)
print(mail_handler.credentials)
mail_handler.setLevel(logging.ERROR)
mail_handler.setFormatter(logging.Formatter('[%(asctime)s] %(levelname)s in %(module)s: %(message)s'))

The print statements and traceback I’m getting is:

my.hosting.com
admin@myapp.com
['admin@myapp.com']
Application Error
()
5.0
Traceback (most recent call last):
  File "C:\Users\user\Documents\myapp\test.py", line 31, in <module>
    print(mail_handler.credentials)
AttributeError: 'SMTPHandler' object has no attribute 'credentials'

When I check the init statement for SMTPHandler using the following snippet to make sure I’m not accessing a very old version (I think credentials was added in 2.6):

import inspect

signature = inspect.signature(SMTPHandler.__init__).parameters
for name, parameter in signature.items():
    print(name, parameter.default, parameter.annotation, parameter.kind)`

I get:

self <class 'inspect._empty'> <class 'inspect._empty'> POSITIONAL_OR_KEYWORD
mailhost <class 'inspect._empty'> <class 'inspect._empty'> POSITIONAL_OR_KEYWORD
fromaddr <class 'inspect._empty'> <class 'inspect._empty'> POSITIONAL_OR_KEYWORD
toaddrs <class 'inspect._empty'> <class 'inspect._empty'> POSITIONAL_OR_KEYWORD
subject <class 'inspect._empty'> <class 'inspect._empty'> POSITIONAL_OR_KEYWORD
credentials None <class 'inspect._empty'> POSITIONAL_OR_KEYWORD
secure None <class 'inspect._empty'> POSITIONAL_OR_KEYWORD
timeout 5.0 <class 'inspect._empty'> POSITIONAL_OR_KEYWORD

So ‘credentials’ is in the initialization statement.

Anyone see something stupid in my code or run into this problem?

Thanks so much!

>Solution :

You have the full source code for all of the standard modules on your computer. I just took a quick look, and although the SMTPHandler accepts a credentials argument, it stores that argument in self.username and self.password.