docs: def store(self, correlation_id, key, credential):
          """
          Stores credential parameters into the store.
  
          :param correlation_id: (optional) transaction id to trace execution through call chain.
  
          :param key: a key to uniquely identify the credential parameters.
  
          :param credential: a credential parameters to be stored.
          """
          if credential != None:
              self._items.put(key, credential)
          else:
              self._items.remove(key)