title: Python Jupyter notebook: Python3 displays, however Python2 runs
body: <p>I am trying to set up my Ubuntu 16.04 server on GSE(Google Compute Engine). I run into a problem here. </p>
  
  <p><a href="https://i.stack.imgur.com/A2iPE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/A2iPE.png" alt="enter image description here"></a></p>
  
  <p>You can see from the up right corner, it is Python 3 kernel already.</p>
  
  <p>For now, I think my the problem occurs because I first followed the instruction from <a href="https://stackoverflow.com/questions/30492623/using-both-python-2-x-and-python-3-x-in-ipython-notebook">Using both Python 2.x and Python 3.x in IPython Notebook</a>:</p>
  
  <ol>
  <li><p>Create this directory: <code>mkdir -p ~/.ipython/kernels/python3</code></p></li>
  <li><p>Create this file <code>~/.ipython/kernels/python3/kernel.json</code> with this </p>
  
  <p>content:
      {
          "display_name": "IPython (Python 3)", 
          "language": "python", 
          "argv": [
              "python3", 
              "-c", "from IPython.kernel.zmq.kernelapp import main; main()", 
              "-f", "{connection_file}"
          ], 
          "codemirror_mode": {
              "version": 2, 
              "name": "ipython"
          }
      }</p>
  
  <p>And then I installed jupyter(for python3 I think) via pip3:</p>
  
  <p>$ sudo apt-get install ipython3
  $ pip3 install jupyter</p></li>
  </ol>
  
  <p>But How am I gonna fix this here?</p>
  
  <p>Thank you!</p>