No module named 'pexpect'

[CPernet]

Hello,

I'm having trouble getting the kernel starting - has anyone encounter this before?

OS: Windows10
Python: WinPython 3.8.1 (windows path setup, Matlab engine set up and running no problem within a notebook)
test: C:\Users\cpernet>python -m matlab_kernel.check

Traceback (most recent call last):
  File "C:\Python\WPy64-3810\python-3.8.1.amd64\lib\runpy.py", line 193, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "C:\Python\WPy64-3810\python-3.8.1.amd64\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "C:\Python\WPy64-3810\python-3.8.1.amd64\lib\site-packages\matlab_kernel\check.py", line 2, in <module>
    from metakernel import __version__ as mversion
  File "C:\Python\WPy64-3810\python-3.8.1.amd64\lib\site-packages\metakernel\__init__.py", line 4, in <module>
    from . import pexpect
  File "C:\Python\WPy64-3810\python-3.8.1.amd64\lib\site-packages\metakernel\pexpect.py", line 6, in <module>
    from pexpect import is_executable_file, EOF, TIMEOUT, __file__ as PEXPECT_DIR
ModuleNotFoundError: No module named 'pexpect'

the kernel is there

C:\Users\cpernet>jupyter kernelspec list
Available kernels:
  matlab     C:\Python\WPy64-3810\python-3.8.1.amd64\share\jupyter\kernels\matlab
  octave     C:\Python\WPy64-3810\python-3.8.1.amd64\share\jupyter\kernels\octave
  python3    C:\Python\WPy64-3810\python-3.8.1.amd64\share\jupyter\kernels\python3

pexpect is there too (and seems the right location)

pip install pexpect
Requirement already satisfied: pexpect in c:\python\wpy64-3810\python-3.8.1.amd64\lib\site-packages (4.7.0+dummy)

but maybe not well installed? all I have is 5 files

Directory of C:\Python\WPy64-3810\python-3.8.1.amd64\Lib\site-packages\pexpect-4.7.0+dummy.dist-info

22/12/2019  15:59    <DIR>          .
22/12/2019  15:59    <DIR>          ..
22/12/2019  15:59                 4 INSTALLER
22/12/2019  15:49             1,268 METADATA
22/12/2019  15:59               420 RECORD
22/12/2019  15:49                 1 top_level.txt
22/12/2019  15:49               116 WHEEL
               5 File(s)          1,809 bytes
               2 Dir(s)  44,141,572,096 bytes free

thx