code: def set_item(self, key, value, timeout = None, timeout_callback = None):
          
          with self._lock:
              logger.debug("expdict.__setitem__({0!r}, {1!r}, {2!r}, {3!r})"
                              .format(key, value, timeout, timeout_callback))
              if not timeout:
                  timeout = self._default_timeout
              self._timeouts[key] = (time.time() + timeout, timeout_callback)
              return dict.__setitem__(self, key, value)
docs: Set item of the dictionary.
  
          :Parameters:
              - `key`: the key.
              - `value`: the object to store.
              - `timeout`: timeout value for the object (in seconds from now).
              - `timeout_callback`: function to be called when the item expires.
                The callback should accept none, one (the key) or two (the key
                and the value) arguments.
          :Types:
              - `key`: any hashable value
              - `value`: any python object
              - `timeout`: `int`
              - `timeout_callback`: callable