How do you check whether a python method is bound or not?

def isbound(method):
    return method.im_self is not None
    
def instance(bounded_method):
    return bounded_method.im_self

User-defined methods:

When a user-defined method object is
created by retrieving a user-defined
function object from a class, its
im_self attribute is None and the
method object is said to be unbound.
When one is created by retrieving a
user-defined function object from a
class via one of its instances, its
im_self attribute is the instance, and
the method object is said to be bound.
In either case, the new method’s
im_class attribute is the class from
which the retrieval takes place, and
its im_func attribute is the original
function object.

In Python 2.6 and 3.0:

Instance method objects have new
attributes for the object and function
comprising the method; the new synonym
for im_self is __self__, and im_func
is also available as __func__. The old
names are still supported in Python
2.6, but are gone in 3.0.