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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def del_watch(self, wd):
 """ Remove watch entry associated to watch descriptor wd. @param wd: Watch descriptor. @type wd: int """

        try:
            del self._wmd[wd]
        except KeyError as err:
            log.error('Cannot delete unknown watch descriptor %s' % str(err))