title: Jupyter notebook fail to start kernel
body: <p>I am new to Jupyter notebook when I try to create a Jupyter notebook, it fail to start the kernel by showing below error message, my python version is 3.5.2 and jupyter version is 4.2.0:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/andy/anaconda3/lib/python3.5/site-packages/traitlets/traitlets.py", line 526, in get
      value = obj._trait_values[self.name]
  KeyError: 'loop'
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/home/andy/anaconda3/lib/python3.5/site-packages/notebook/base/handlers.py", line 457, in wrapper
      result = yield gen.maybe_future(method(self, *args, **kwargs))
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 1133, in run
      value = future.result()
    File "/home/andy/anaconda3/lib/python3.5/asyncio/futures.py", line 274, in result
      raise self._exception
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 1141, in run
      yielded = self.gen.throw(*exc_info)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/notebook/services/sessions/handlers.py", line 62, in post
      kernel_id=kernel_id))
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 1133, in run
      value = future.result()
    File "/home/andy/anaconda3/lib/python3.5/asyncio/futures.py", line 274, in result
      raise self._exception
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 1141, in run
      yielded = self.gen.throw(*exc_info)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/notebook/services/sessions/sessionmanager.py", line 79, in create_session
      kernel_name)
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 1133, in run
      value = future.result()
    File "/home/andy/anaconda3/lib/python3.5/asyncio/futures.py", line 274, in result
      raise self._exception
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 1141, in run
      yielded = self.gen.throw(*exc_info)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/notebook/services/sessions/sessionmanager.py", line 92, in start_kernel_for_session
      self.kernel_manager.start_kernel(path=kernel_path, kernel_name=kernel_name)
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 1133, in run
      value = future.result()
    File "/home/andy/anaconda3/lib/python3.5/asyncio/futures.py", line 274, in result
      raise self._exception
    File "/home/andy/.local/lib/python3.5/site-packages/tornado/gen.py", line 326, in wrapper
      yielded = next(result)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/notebook/services/kernels/kernelmanager.py", line 87, in start_kernel
      super(MappingKernelManager, self).start_kernel(**kwargs)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/jupyter_client/multikernelmanager.py", line 110, in start_kernel
      km.start_kernel(**kwargs)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/jupyter_client/manager.py", line 258, in start_kernel
      self.start_restarter()
    File "/home/andy/anaconda3/lib/python3.5/site-packages/jupyter_client/ioloop/manager.py", line 49, in start_restarter
      kernel_manager=self, loop=self.loop,
    File "/home/andy/anaconda3/lib/python3.5/site-packages/traitlets/traitlets.py", line 554, in __get__
      return self.get(obj, cls)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/traitlets/traitlets.py", line 533, in get
      value = self._validate(obj, dynamic_default())
    File "/home/andy/anaconda3/lib/python3.5/site-packages/traitlets/traitlets.py", line 589, in _validate
      value = self.validate(obj, value)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/traitlets/traitlets.py", line 1681, in validate
      self.error(obj, value)
    File "/home/andy/anaconda3/lib/python3.5/site-packages/traitlets/traitlets.py", line 1528, in error
      raise TraitError(e)
  traitlets.traitlets.TraitError: The 'loop' trait of an IOLoopKernelManager instance must be a ZMQIOLoop, but a value of class 'tornado.platform.asyncio.AsyncIOMainLoop' (i.e. &lt;tornado.platform.asyncio.AsyncIOMainLoop object at 0x7f1dd34e8ef0&gt;) was specified.
  </code></pre>
  
  <p>And I have also checked the kernel by using below command:</p>
  
  <pre><code>jupyter kernelspec list
  </code></pre>
  
  <p>Get below result:</p>
  
  <pre><code>Available kernels:
  python3    /home/andy/anaconda3/share/jupyter/kernels/python3
  </code></pre>
  
  <p>Can anyone help me?</p>