human
Solve the following python programming problem given the following code:
def replaceSysModules(self, sysModules) : 
    '
        Replace sys.modules, for the duration of the test, with the given value.
        ' 
    originalSysModules = sys.modules.copy () 
    def cleanUpSysModules() : 
        sys.modules.clear () 
        sys.modules.update (originalSysModules) 
self.addCleanup (<MASK>) 
    sys.modules.clear () 
    sys.modules.update (sysModules) 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is a proper replacement for <MASK>.
def cleanUpSysModules(