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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 verify(self):
 """ Verify that the cached values are still for the same value of id_function and delete all stored items if the value of id_function has changed. """

        # if we are in a lock don't check anything
        if self._lock != 0:
            return

        # check the hash of our data
        id_new = self._id_function()

        # things changed
        if id_new != self.id_current:
            if len(self.cache) > 0:
                log.debug('%d items cleared from cache: %s',
                          len(self.cache),
                          str(list(self.cache.keys())))
            # hash changed, so dump the cache
            # do it manually rather than calling clear()
            # as we are internal logic and can avoid function calls
            self.cache = {}
            # set the id to the new data hash
            self.id_current = id_new