FEAT: Add flake8 (#267)

* init flake8

* exclude nostr client, and add ds_store to gitignore

* fix flake8 F811 issue, redefinition of unused variables

* add flake8 to workflow

* F401 unused imports

* F541 f-string is missing placeholders

* E501 line too long > 150 characters

* E722 no bare except

* E402 module level import not at top of file

* F405 no star imports

* E712 comparison to False should be 'if cond is False:'

* F841 local variable is assigned to but never used

* E266 too many leading '#' for block comment

* E265, E261

* E713 test for membership should be 'not in'

* E711, E741

E741 ambiguous variable name 'l'
E711 comparison to None should be 'if cond is None:'

* flake config

* isort

* refactor makefile flake8 usage

* reflaking the rebase

* black

* fix tests?

* black

* fix line lenght it test_cli

* sort out makefile

* fix strings

* reintroduce black-check

* reflake and mypy

* isort

* Update cashu/wallet/wallet.py

Co-authored-by: Angus Pearson <angus@toaster.cc>

* Update cashu/mint/ledger.py

Co-authored-by: Angus Pearson <angus@toaster.cc>

---------

Co-authored-by: Angus Pearson <angus@toaster.cc>

Makefile

@@ -8,16 +8,18 @@ black:
 	poetry run black . --exclude cashu/nostr
 
 black-check:
-	poetry run black --check . --exclude cashu/nostr
-
-format:
-	make isort
-	make black
-	make mypy
+	poetry run black . --exclude cashu/nostr --check
 
 mypy:
 	poetry run mypy cashu --ignore-missing
 
+flake8:
+	poetry run flake8
+
+format: isort black
+
+check: mypy flake8 isort-check black-check
+
 clean:
 	rm -r cashu.egg-info/ || true
 	find . -name ".DS_Store" -exec rm -f {} \; || true