How to list attributes of a Python object without __dict__

Usually you can list all attributes and functions of a Python object using __dir__:

from collections import namedtuple
nt = namedtuple("Foo", [])
print(nt.__dict__) # Prints attributes and functions of nt.

This can be very useful to find out e.g. which functions you can call on an object:

However for some objects like datetime.datetime this doesn’t work. Attempting to run

from datetime import datetime
dt = datetime.now()
print(dt.__dict__)

will result in

Traceback (most recent call last):
  File "test.py", line 3, in <module>
AttributeError: 'datetime.datetime' object has no attribute '__dict__'

So how can you find out which attributes your datetime.datetime object has and what function you can call on it?

Use dir():

from datetime import datetime
dt = datetime.now()
print(dir(dt))

This will print e.g.

['__add__', '__class__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__ne__', '__new__', '__radd__', '__reduce__', '__reduce_ex__', '__repr__', '__rsub__', '__setattr__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', 'astimezone', 'combine', 'ctime', 'date', 'day', 'dst', 'fold', 'fromordinal', 'fromtimestamp', 'hour', 'isocalendar', 'isoformat', 'isoweekday', 'max', 'microsecond', 'min', 'minute', 'month', 'now', 'replace', 'resolution', 'second', 'strftime', 'strptime', 'time', 'timestamp', 'timetuple', 'timetz', 'today', 'toordinal', 'tzinfo', 'tzname', 'utcfromtimestamp', 'utcnow', 'utcoffset', 'utctimetuple', 'weekday', 'year']