No module named 'prompt_toolkit.formatted_text'
Check your environment variable Path!
In the system variable Path add the following line

C:\Users\\AppData\Roaming\Python\Python37\Scripts
I am totally new to Jupyter Notebook.
Currently, I am using the notebook with R and it is working well.
Now, I tried to use it with Python and I receive the following error.

[I 09:00:52.947 NotebookApp] KernelRestarter: restarting kernel (4/5),
  new random ports
Traceback (most recent call last):
File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
  "main", mod_spec)
File "/usr/lib/python3.6/runpy.py", line 85, in _run_code exec(code,
  run_globals)
File
  "/home/frey/.local/lib/python3.6/site-packages/ipykernel_launcher.py",
  line 15, in  from ipykernel import kernelapp as app
File
  "/home/frey/.local/lib/python3.6/site-packages/ipykernel/init.py",
  line 2, in  from .connect import *
File
  "/home/frey/.local/lib/python3.6/site-packages/ipykernel/connect.py",
  line 13, in  from IPython.core.profiledir import ProfileDir
File "/home/frey/.local/lib/python3.6/site-packages/IPython/init.py",
  line 55, in  from .terminal.embed import embed
File
  "/home/frey/.local/lib/python3.6/site-packages/IPython/terminal/embed.py",
  line 16, in  from IPython.terminal.interactiveshell import
  TerminalInteractiveShell
File
  "/home/frey/.local/lib/python3.6/site-packages/IPython/terminal/interactiveshell.py",
  line 20, in  from prompt_toolkit.formatted_text import PygmentsTokens
  ModuleNotFoundError: No module named 'prompt_toolkit.formatted_text'
[W 09:00:55.956 NotebookApp] KernelRestarter: restart failed [W
  09:00:55.956 NotebookApp] Kernel 24117cd7-38e5-4978-8bda-d1b84f498051
  died, removing from map.

Hopefully, someone can help me.