How to use the fasteners.locked function in fasteners

    @fasteners.locked
    def break_(self):
        reply = self.client.delete(self._lock_url, make_url=False)
        return reply.get('errorCode') is None

    @fasteners.locked
    def compile(self):
        """Compiles the contained item into a compiled equivalent."""
        if self._compilation is None:
            self._pre_compile()
            try:
                graph, node = self._compile(self._root, parent=None)
            except Exception:
                with excutils.save_and_reraise_exception():
                    # Always clear the history, to avoid retaining junk
                    # in memory that isn't needed to be in memory if
                    # compilation fails...
                    self._history.clear()
            else:
                self._post_compile(graph, node)
                if self._freeze:
                    graph.freeze()

    @fasteners.locked(lock='_open_close_lock')
    def close(self):
        if self._owned:
            LOG.debug("Stopping client")
            self._closing = True
            kazoo_utils.finalize_client(self._client)
        if self._worker is not None:
            LOG.debug("Shutting down the notifier")
            self._worker.shutdown()
            self._worker = None
        with self._job_cond:
            self._known_jobs.clear()
        LOG.debug("Stopped & cleared local state")
        self._connected = False
        self._last_states.clear()

    @fasteners.locked(lock='_open_close_lock')
    def close(self):
        if self._owns_client:
            self._client.close()
        self._scripts.clear()
        self._redis_version = None
        self._closed = True

    @fasteners.locked
    def close(self):
        """Closes the contained jobboard, disallowing further use."""
        self._jobboard.close()

    @fasteners.locked
    def heartbeat(self):
        """Keep the lock alive."""
        if self.acquired:
            poked = self.client.put(self._lock_url,
                                    data={"ttl": self.ttl,
                                          "prevExist": "true"}, make_url=False)
            self._node = poked['node']
            errorcode = poked.get("errorCode")
            if not errorcode:
                return True
            LOG.warning("Unable to heartbeat by updating key '%s' with "
                        "extended expiry of %s seconds: %d, %s", self.name,
                        self.ttl, errorcode, poked.get("message"))
        return False

    @fasteners.locked
    def connect(self):
        """Ensures the jobboard is connected (noop if it is already)."""
        if not self._jobboard.connected:
            self._jobboard.connect()

    @fasteners.locked
    @_pre_check(check_storage_ensured=False, check_validated=False)
    def prepare(self):
        if not self._storage_ensured:
            # Set our own state to resuming -> (ensure atoms exist
            # in storage) -> suspended in the storage unit and notify any
            # attached listeners of these changes.
            self._change_state(states.RESUMING)
            self._ensure_storage()
            self._change_state(states.SUSPENDED)
            self._storage_ensured = True
        # Reset everything back to pending (if we were previously reverted).
        if self.storage.get_flow_state() == states.REVERTED:
            self.reset()

    @fasteners.locked
    @_pre_check(check_validated=False)
    def validate(self):
        # At this point we can check to ensure all dependencies are either
        # flow/task provided or storage provided, if there are still missing
        # dependencies then this flow will fail at runtime (which we can avoid
        # by failing at validation time).
        if LOG.isEnabledFor(logging.TRACE):
            execution_graph = self._compilation.execution_graph
            LOG.trace("Validating scoping and argument visibility for"
                      " execution graph with %s nodes and %s edges with"
                      " density %0.3f", execution_graph.number_of_nodes(),
                      execution_graph.number_of_edges(),
                      nx.density(execution_graph))
        missing = set()
        # Attempt to retain a chain of what was missing (so that the final
        # raised exception for the flow has the nodes that had missing