[Python] How to decorate the __enter__ and __exit__ instance methods?

I would like to use the decorator deco to reshape the __enter__ and __exit__ instance methods. The code runs but the wrapper is not executed in the with section. Find the actual output below, followed by expected output and finally the code.

Current output:

In __init__
-------------------
In __enter__
-------------------
In wrapper
Blah, blah, blah
-------------------
In __exit__


Expected output:

In __init__
-------------------
In wrapper
In __enter__
-------------------
In wrapper
Blah, blah, blah
-------------------
In wrapper
In __exit__


class contMgr():
def __init__(self):
print("In __init__")
pass

def __enter__(self):
print("In __enter__")
return self

def __exit__(self, exc_type, exc_val, exc_tb):
print("In __exit__")
pass

def __call__(self, *args, **kwargs):
print("In __call_")

def brol():
print("brol")

def deco(func):
def wrapper(*args,**kwargs):
print("In wrapper")
result = func(*args, **kwargs)
return result

return wrapper

@Deco
def test():
print("Blah, blah, blah")

mgr = contMgr()
mgr.__enter__ = deco(mgr.__enter__)
mgr.__exit__ = deco(mgr.__exit__)
print("------------------------")
with mgr:
print("------------------------")
test()
print("------------------------")

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