Replaces the entry for a key only if it is currently mapped to some value.

        This is equivalent to:
            >>> if map.contains_key(key):
            >>>     return map.put(key,value)
            >>> else:
            >>>     return None
        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.

def replace(self, key, value):
        """
        Replaces the entry for a key only if it is currently mapped to some value.

        This is equivalent to:
            >>> if map.contains_key(key):
            >>>     return map.put(key,value)
            >>> else:
            >>>     return None
        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)