Python : How to check whether a variable is a class or not?

Question

I was wondering how to check whether a variable is a class (not an instance!) or not.

I've tried to use the function isinstance(object, class_or_type_or_tuple) to do this, but I don't know what type would a class will have.

For example, in the following code

class Foo: pass  
isinstance(Foo, **???**) # i want to make this return True.

I tried to substitute "class" with ???, but I realized that class is a keyword in python.

Any help? Thanks.

Answer 1

>>> class X(object):
...     pass
... 
>>> type(X)
<type 'type'>
>>> isinstance(X,type)
True

Answer 2

Even better: use the inspect module.

>>> import inspect
>>> class X(object):
...     pass
... 
>>> inspect.isclass(X)
True

Answer 3

class Foo: is called old style class and class X(object): is called new style class.

Check this http://stackoverflow.com/questions/54867/old-style-and-new-style-classes-in-python . New style is recommended. Read about "unifying types and classes"