<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def shortDescription(self):
        '''
        Overrides property from Event base class.
        '''
        cd = getattr(self,'classDescription',None)
        if cd:
            sd = getattr(cd,'shortDescription','')
            d = getattr(cd,'description','')
            return sd if sd else d
        return ''