using self-developed modules

[snippsat]

But when I display in Python "pprint (sys.path)", the folder does not show up.
Strange!

No it's not strange,there is no connection between Environment Variables(OS) and sys.path(Python).
Example i have a folder C:\nc in System Variables Path.
Same code as before saved as eggs.py in this folder.

# eggs.py
def f1(x):
    x = x + 1
    return x

C:\Users\Tom
λ python
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 21:26:53) [MSC v.1916 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import eggs
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'eggs'

# Most add nc to sys.path,so python find it
>>> import sys
>>> sys.path.append(r'C:\nc') # Only temporarily added in this session 

# Now it work
>>> import eggs

>>> eggs.f1(799)
800

As i explain link before in this post.
Using site will add folder permanent to sys.path,this mean that dos not need to add a folder to System or User Variables Path.
As long as Python is System Variables as eg you have here:

C:\Users\actname\AppData\Local\Programs\Python\Python37-32\Scripts\;
C:\Users\actname\AppData\Local\Programs\Python\Python37-32\