title: Problems upgrading Ipython (prompt_toolkit incompatibilities)
body: <p>Trying to open a jupyter notebook file (.ipynb file) 
  with this command <code>ipython notebook filename.ipynb</code> then I am getting Below Error while using ipython..</p>
  
  <pre><code>Traceback (most recent call last):
  File "c:\python\lib\runpy.py", line 193, in _run_module_as_main
  "__main__", mod_spec)
  File "c:\python\lib\runpy.py", line 85, in _run_code
  exec(code, run_globals)
  File "C:\Python\Scripts\ipython.exe\__main__.py", line 5, in &lt;module&gt;
  File "c:\python\lib\site-packages\IPython\__init__.py", line 55, in &lt;module&gt;
  from .terminal.embed import embed
  File "c:\python\lib\site-packages\IPython\terminal\embed.py", line 16, in 
  &lt;module&gt;
  from IPython.terminal.interactiveshell import TerminalInteractiveShell
  File "c:\python\lib\site-packages\IPython\terminal\interactiveshell.py", 
  line 18, in &lt;module&gt;
  from prompt_toolkit.enums import DEFAULT_BUFFER, EditingMode
  ModuleNotFoundError: No module named 'prompt_toolkit'
  </code></pre>