Can't use closure function for subscribe callback function

[windslinux]

from pubsub import pub

def localCall(func):
def real_func(data):
print("In real function : {}".format(data))
func(data)
return real_func

def localUpdate(data):
print("In local update")

pub.subscribe(localCall(localUpdate), "update")
pub.sendMessage("update", data="updateUI")

In the example above, the function localUpdate can't be called. I have no idea why the closure function can't be called?