prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  Replacing periodic.period doesn't change period
  ```
  import panel as pn
  pn.extension()
  
  test = pn.widgets.Toggle(name='Test')
  
  def toggle():
      test.value = not test.value
  
  periodic = test.add_periodic_callback(toggle, period=1000)
  test
  ```
  
  ```
  periodic.period = 20000  #this doesnt update the periodic milliseconds
  ```
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `panel/callbacks.py`
  Content:
  ```
  1 """
  2 Defines callbacks to be executed on a thread or by scheduling it
  3 on a running bokeh server.
  4 """
  5 from __future__ import absolute_import, division, unicode_literals
  6 
  7 
  8 import time
  9 import param
  10 
  11 from bokeh.io import curdoc as _curdoc
  12 
  13 
  14 class PeriodicCallback(param.Parameterized):
  15     """
  16     Periodic encapsulates a periodic callback which will run both
  17     in tornado based notebook environments and on bokeh server. By
  18     default the callback will run until the stop method is called,
  19     but count and timeout values can be set to limit the number of
  20     executions or the maximum length of time for which the callback
  21     will run.
  22     """
  23 
  24     callback = param.Callable(doc="""
  25        The callback to execute periodically.""")
  26 
  27     count = param.Integer(default=None, doc="""
  28         Number of times the callback will be executed, by default
  29         this is unlimited.""")
  30 
  31     period = param.Integer(default=500, doc="""
  32         Period in milliseconds at which the callback is executed.""")
  33 
  34     timeout = param.Integer(default=None, doc="""
  35         Timeout in seconds from the start time at which the callback
  36         expires""")
  37 
  38     def __init__(self, **params):
  39         super(PeriodicCallback, self).__init__(**params)
  40         self._counter = 0
  41         self._start_time = None
  42         self._timeout = None
  43         self._cb = None
  44         self._doc = None
  45 
  46     def start(self):
  47         if self._cb is not None:
  48             raise RuntimeError('Periodic callback has already started.')
  49         self._start_time = time.time()
  50         if _curdoc().session_context:
  51             self._doc = _curdoc()
  52             self._cb = self._doc.add_periodic_callback(self._periodic_callback, self.period)
  53         else:
  54             from tornado.ioloop import PeriodicCallback
  55             self._cb = PeriodicCallback(self._periodic_callback, self.period)
  56             self._cb.start()
  57 
  58     def _periodic_callback(self):
  59         self.callback()
  60         self._counter += 1
  61         if self._timeout is not None:
  62             dt = (time.time() - self._start_time)
  63             if dt > self._timeout:
  64                 self.stop()
  65         if self._counter == self.count:
  66             self.stop()
  67 
  68     def stop(self):
  69         self._counter = 0
  70         self._timeout = None
  71         if self._doc:
  72             self._doc.remove_periodic_callback(self._cb)
  73         else:
  74             self._cb.stop()
  75         self._cb = None
  76 
  77
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/panel/callbacks.py b/panel/callbacks.py
  --- a/panel/callbacks.py
  +++ b/panel/callbacks.py
  @@ -55,6 +55,12 @@
               self._cb = PeriodicCallback(self._periodic_callback, self.period)
               self._cb.start()
   
  +    @param.depends('period', watch=True)
  +    def _update_period(self):
  +        if self._cb:
  +            self.stop()
  +            self.start()
  +
       def _periodic_callback(self):
           self.callback()
           self._counter += 1
  
verification_info: {"golden_diff": "diff --git a/panel/callbacks.py b/panel/callbacks.py\n--- a/panel/callbacks.py\n+++ b/panel/callbacks.py\n@@ -55,6 +55,12 @@\n             self._cb = PeriodicCallback(self._periodic_callback, self.period)\n             self._cb.start()\n \n+    @param.depends('period', watch=True)\n+    def _update_period(self):\n+        if self._cb:\n+            self.stop()\n+            self.start()\n+\n     def _periodic_callback(self):\n         self.callback()\n         self._counter += 1\n", "issue": "Replacing periodic.period doesn't change period\n```\r\nimport panel as pn\r\npn.extension()\r\n\r\ntest = pn.widgets.Toggle(name='Test')\r\n\r\ndef toggle():\r\n    test.value = not test.value\r\n\r\nperiodic = test.add_periodic_callback(toggle, period=1000)\r\ntest\r\n```\r\n\r\n```\r\nperiodic.period = 20000  #this doesnt update the periodic milliseconds\r\n```\n", "before_files": [{"content": "\"\"\"\nDefines callbacks to be executed on a thread or by scheduling it\non a running bokeh server.\n\"\"\"\nfrom __future__ import absolute_import, division, unicode_literals\n\n\nimport time\nimport param\n\nfrom bokeh.io import curdoc as _curdoc\n\n\nclass PeriodicCallback(param.Parameterized):\n    \"\"\"\n    Periodic encapsulates a periodic callback which will run both\n    in tornado based notebook environments and on bokeh server. By\n    default the callback will run until the stop method is called,\n    but count and timeout values can be set to limit the number of\n    executions or the maximum length of time for which the callback\n    will run.\n    \"\"\"\n\n    callback = param.Callable(doc=\"\"\"\n       The callback to execute periodically.\"\"\")\n\n    count = param.Integer(default=None, doc=\"\"\"\n        Number of times the callback will be executed, by default\n        this is unlimited.\"\"\")\n\n    period = param.Integer(default=500, doc=\"\"\"\n        Period in milliseconds at which the callback is executed.\"\"\")\n\n    timeout = param.Integer(default=None, doc=\"\"\"\n        Timeout in seconds from the start time at which the callback\n        expires\"\"\")\n\n    def __init__(self, **params):\n        super(PeriodicCallback, self).__init__(**params)\n        self._counter = 0\n        self._start_time = None\n        self._timeout = None\n        self._cb = None\n        self._doc = None\n\n    def start(self):\n        if self._cb is not None:\n            raise RuntimeError('Periodic callback has already started.')\n        self._start_time = time.time()\n        if _curdoc().session_context:\n            self._doc = _curdoc()\n            self._cb = self._doc.add_periodic_callback(self._periodic_callback, self.period)\n        else:\n            from tornado.ioloop import PeriodicCallback\n            self._cb = PeriodicCallback(self._periodic_callback, self.period)\n            self._cb.start()\n\n    def _periodic_callback(self):\n        self.callback()\n        self._counter += 1\n        if self._timeout is not None:\n            dt = (time.time() - self._start_time)\n            if dt > self._timeout:\n                self.stop()\n        if self._counter == self.count:\n            self.stop()\n\n    def stop(self):\n        self._counter = 0\n        self._timeout = None\n        if self._doc:\n            self._doc.remove_periodic_callback(self._cb)\n        else:\n            self._cb.stop()\n        self._cb = None\n\n", "path": "panel/callbacks.py"}], "after_files": [{"content": "\"\"\"\nDefines callbacks to be executed on a thread or by scheduling it\non a running bokeh server.\n\"\"\"\nfrom __future__ import absolute_import, division, unicode_literals\n\n\nimport time\nimport param\n\nfrom bokeh.io import curdoc as _curdoc\n\n\nclass PeriodicCallback(param.Parameterized):\n    \"\"\"\n    Periodic encapsulates a periodic callback which will run both\n    in tornado based notebook environments and on bokeh server. By\n    default the callback will run until the stop method is called,\n    but count and timeout values can be set to limit the number of\n    executions or the maximum length of time for which the callback\n    will run.\n    \"\"\"\n\n    callback = param.Callable(doc=\"\"\"\n       The callback to execute periodically.\"\"\")\n\n    count = param.Integer(default=None, doc=\"\"\"\n        Number of times the callback will be executed, by default\n        this is unlimited.\"\"\")\n\n    period = param.Integer(default=500, doc=\"\"\"\n        Period in milliseconds at which the callback is executed.\"\"\")\n\n    timeout = param.Integer(default=None, doc=\"\"\"\n        Timeout in seconds from the start time at which the callback\n        expires\"\"\")\n\n    def __init__(self, **params):\n        super(PeriodicCallback, self).__init__(**params)\n        self._counter = 0\n        self._start_time = None\n        self._timeout = None\n        self._cb = None\n        self._doc = None\n\n    def start(self):\n        if self._cb is not None:\n            raise RuntimeError('Periodic callback has already started.')\n        self._start_time = time.time()\n        if _curdoc().session_context:\n            self._doc = _curdoc()\n            self._cb = self._doc.add_periodic_callback(self._periodic_callback, self.period)\n        else:\n            from tornado.ioloop import PeriodicCallback\n            self._cb = PeriodicCallback(self._periodic_callback, self.period)\n            self._cb.start()\n\n    @param.depends('period', watch=True)\n    def _update_period(self):\n        if self._cb:\n            self.stop()\n            self.start()\n\n    def _periodic_callback(self):\n        self.callback()\n        self._counter += 1\n        if self._timeout is not None:\n            dt = (time.time() - self._start_time)\n            if dt > self._timeout:\n                self.stop()\n        if self._counter == self.count:\n            self.stop()\n\n    def stop(self):\n        self._counter = 0\n        self._timeout = None\n        if self._doc:\n            self._doc.remove_periodic_callback(self._cb)\n        else:\n            self._cb.stop()\n        self._cb = None\n\n", "path": "panel/callbacks.py"}]}