Resets all stored frequencies for the cache

        :keyword int frequency: Frequency to reset to, must be >= 0

def reset_frequencies(self, frequency=0):
        """Resets all stored frequencies for the cache

        :keyword int frequency: Frequency to reset to, must be >= 0"""

        frequency = max(frequency, 0)

        for key in self._store.keys():
            self._store[key] = (self._store[key][0], frequency)

        return frequency