Refactor mwe module

[leobeeson]

Refactor MWE Module

Resolves #35 .

Situation

• Some methods in MWE class produce IO side effects, which could potentially:
  1. Affect client applications' performance.
  2. Generate storage volume integration problems in cloud environments (e.g. running as lambda functions).

Solution

1. Write unit tests ahead of refactoring to prevent breaking changes (i.e. refactor with TDD).
2. Split methods that do more than one thing (at least unrelated things), such as a calculation alongside a read/write I/O operations.
3. Rename variable and method names to generalise MWE extraction beyond just noun compounds.

NB

• Setting this PR initially as draft request to push small changes related to the same issue.

[meghdadFar]

Thanks, @leobeeson! <3
See my comments below.
We also can drop __init__.py in the test directory. Pytest modules don't need it and Pytest docs recommend not including them. See here.

[meghdadFar]

Please see my comments below.

[meghdadFar]

@leobeeson when running pre-commit, I get a bunch of PEP and static type errors thrown by pre-commit (flake8 and mypy). I wonder if you use the instructions here. I always use pre-commit and it's pretty helpful. First, isort and black edit the code to a nice format, and then mypy runs and checks static types and a bunch of other things, preventing many future run time errors, practically making the code much more stable.

If you install pre-commit following the instructions above, it runs each time that you commit code, blocking the commit until the issues are addressed.

For the already committed code, you can simply run pre-commit run --files <your_file.py>.

Here is a screenshot of the pre-commit (mypy, flake8) errors in am.py

[meghdadFar]

Looks great, Thanks!