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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 replace(self, key, value):
 """ Replaces the entry for a key only if it is currently mapped to some value. This is equivalent to: except that the action is performed atomically. **Warning: This method uses __hash__ and __eq__ methods of binary form of the key, not the actual implementations of __hash__ and __eq__ defined in key's class.** **Warning 2: This method returns a clone of the previous value, not the original (identically equal) value previously put into the map.** :param key: (object), the specified key. :param value: (object), the value to replace the previous value. :return: (object), previous value associated with key, or ``None`` if there was no mapping for key. """

        check_not_none(key, "key can't be None")
        check_not_none(value, "value can't be None")

        key_data = self._to_data(key)
        value_data = self._to_data(value)

        return self._replace_internal(key_data, value_data)