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>

cashu/wallet/crud.py

@@ -1,8 +1,7 @@
-import json
 import time
 from typing import Any, List, Optional, Tuple
 
-from ..core.base import Invoice, KeyBase, P2SHScript, Proof, WalletKeyset
+from ..core.base import Invoice, P2SHScript, Proof, WalletKeyset
 from ..core.db import Connection, Database
 
 
@@ -59,7 +58,7 @@ async def invalidate_proof(
     conn: Optional[Connection] = None,
 ):
     await (conn or db).execute(
-        f"""
+        """
         DELETE FROM proofs
         WHERE secret = ?
         """,
@@ -250,7 +249,7 @@ async def store_lightning_invoice(
     conn: Optional[Connection] = None,
 ):
     await (conn or db).execute(
-        f"""
+        """
         INSERT INTO invoices
           (amount, pr, hash, preimage, paid, time_created, time_paid)
         VALUES (?, ?, ?, ?, ?, ?, ?)
@@ -395,7 +394,7 @@ async def set_nostr_last_check_timestamp(
     conn: Optional[Connection] = None,
 ):
     await (conn or db).execute(
-        f"UPDATE nostr SET last = ? WHERE type = ?",
+        "UPDATE nostr SET last = ? WHERE type = ?",
         (timestamp, "dm"),
     )
 
@@ -405,7 +404,7 @@ async def get_nostr_last_check_timestamp(
     conn: Optional[Connection] = None,
 ):
     row = await (conn or db).fetchone(
-        f"""
+        """
         SELECT last from nostr WHERE type = ?
         """,
         ("dm",),
@@ -418,7 +417,7 @@ async def get_seed_and_mnemonic(
     conn: Optional[Connection] = None,
 ) -> Optional[Tuple[str, str]]:
     row = await (conn or db).fetchone(
-        f"""
+        """
         SELECT seed, mnemonic from seed
         """,
     )
@@ -439,7 +438,7 @@ async def store_seed_and_mnemonic(
     conn: Optional[Connection] = None,
 ):
     await (conn or db).execute(
-        f"""
+        """
         INSERT INTO seed
           (seed, mnemonic)
         VALUES (?, ?)