Use the following attribute:
cls.__bases__
From the docs:
The tuple of base classes of a class object.
Example:
>>> str.__bases__
(<type 'basestring'>,)
Another example:
>>> class A(object):
... pass
...
>>> class B(object):
... pass
...
>>> class C(A, B):
... pass
...
>>> C.__bases__
(<class '__main__.A'>, <class '__main__.B'>)
If you want all the ancestors rather than just the immediate ones, use inspect.getmro:
import inspect
print inspect.getmro(cls)
Usefully, this gives you all ancestor classes in the "method resolution order" -- i.e. the order in which the ancestors will be checked when resolving a method (or, actually, any other attribute -- methods and other attributes live in the same namespace in Python, after all;-).
Use bases if you just want to get the parents, use __mro__ (as pointed out by @naught101) for getting the method resolution order (so to know in which order the init's were executed).
Bases (and first getting the class for an existing object):
>>> some_object = "some_text"
>>> some_object.__class__.__bases__
(object,)
For mro in recent Python versions:
>>> some_object = "some_text"
>>> some_object.__class__.__mro__
(str, object)
Obviously, when you already have a class definition, you can just call __mro__ on that directly:
>>> class A(): pass
>>> A.__mro__
(__main__.A, object)
If you want to ensure they all get called, use super at all levels.
The FASTEST way, to see all parents, and IN ORDER, just use the built in __mro__
i.e. repr(YOUR_CLASS.__mro__)
>>>
>>>
>>> import getpass
>>> getpass.GetPassWarning.__mro__
outputs, IN ORDER
(<class 'getpass.GetPassWarning'>, <type 'exceptions.UserWarning'>,
<type 'exceptions.Warning'>, <type 'exceptions.Exception'>,
<type 'exceptions.BaseException'>, <type 'object'>)
>>>
There you have it. The "best" answer right now, has 182 votes (as I am typing this) but this is SO much simpler than some convoluted for loop, looking into bases one class at a time, not to mention when a class extends TWO or more parent classes. Importing and using inspect just clouds the scope unnecessarily. It honestly is a shame people don't know to just use the built-ins
I Hope this Helps!
New-style classes have an mro method you can call which returns a list of parent classes in method resolution order.
Source: Stackoverflow.com