From f31e5999faae958fb9842ac29cd374a8b9014109 Mon Sep 17 00:00:00 2001
From: Gaurav Jadhav <gaurav.vjadhav01@gmail.com>
Date: Thu, 10 Sep 2026 14:23:24 +0530
Subject: [PATCH] MAINT: Code-hygiene quick wins (#882)

Address the remaining items of the July 2026 audit's hygiene list. Item 1
(common_messages.py) is already gone from main.

- quantecon/__init__.py: the bare except around the numba import caught
  KeyboardInterrupt and SystemExit and dropped the original exception. Catch
  ImportError, chain it with "from e", and name pip as well as conda.
- tests/test_quadsum.py: drop the nose-era __main__ block. It called three
  undefined names and was the source of every F821 in the package.
- _dle.py, util/notebooks.py: replace "isinstance(...) == True" and
  "type(x) == list" / "type(x) != np.ndarray" with plain isinstance checks.
- tests/test_graph_tools.py: bare except becomes except KeyError.
- util/timing.py: Timer.__exit__ binds none of its three arguments, so take
  *exc_info instead.
- game_theory/game_generators/__init__.py: import the five generators
  explicitly and declare __all__, which lets the file drop its flake8 noqa.
  The exported names are unchanged.

flake8 --select=F821,E722,E712,E721 quantecon goes from 7 violations to none.
No behaviour change intended.
---
 quantecon/__init__.py                             | 6 +++---
 quantecon/_dle.py                                 | 4 ++--
 quantecon/game_theory/game_generators/__init__.py | 9 +++++++--
 quantecon/tests/test_graph_tools.py               | 2 +-
 quantecon/tests/test_quadsum.py                   | 8 --------
 quantecon/util/notebooks.py                       | 2 +-
 quantecon/util/timing.py                          | 2 +-
 7 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/quantecon/__init__.py b/quantecon/__init__.py
index b88d762fb..fabf9ab27 100644
--- a/quantecon/__init__.py
+++ b/quantecon/__init__.py
@@ -7,10 +7,10 @@
 
 try:
     import numba
-except:
+except ImportError as e:
     raise ImportError(
-        "Cannot import numba from current anaconda distribution. \
-            Please run `conda install numba` to install the latest version.")
+        "Cannot import numba, which QuantEcon.py requires. Install it with "
+        "`pip install numba` or `conda install numba`.") from e
 
 #-Modules-#
 from . import distributions
diff --git a/quantecon/_dle.py b/quantecon/_dle.py
index ceeaee7f1..7bafed20d 100644
--- a/quantecon/_dle.py
+++ b/quantecon/_dle.py
@@ -243,7 +243,7 @@ def compute_sequence(self, x0, ts_length=None, Pay=None):
 
         # === Value of asset whose payout vector is Pay*xt === #
         # See p.145: Equation (7.11.1)
-        if isinstance(Pay, np.ndarray) == True:
+        if isinstance(Pay, np.ndarray):
             self.Za = Pay.T @ self.Mc
             self.Q = solve_discrete_lyapunov(
                 self.A0.T * self.beta**0.5, self.Za)
@@ -277,7 +277,7 @@ def irf(self, ts_length=100, shock=None):
 
         """
 
-        if type(shock) != np.ndarray:
+        if not isinstance(shock, np.ndarray):
             # Default is to select first element of w
             shock = np.vstack((np.ones((1, 1)), np.zeros((self.nw - 1, 1))))
 
diff --git a/quantecon/game_theory/game_generators/__init__.py b/quantecon/game_theory/game_generators/__init__.py
index fa20a29ea..1b51543b5 100644
--- a/quantecon/game_theory/game_generators/__init__.py
+++ b/quantecon/game_theory/game_generators/__init__.py
@@ -1,6 +1,11 @@
-# flake8: noqa
 """
 game_theory.game_generators
 
 """
-from .bimatrix_generators import *
+from .bimatrix_generators import (blotto_game, ranking_game, sgc_game,
+                                  tournament_game, unit_vector_game)
+
+__all__ = [
+    'blotto_game', 'ranking_game', 'sgc_game', 'tournament_game',
+    'unit_vector_game'
+]
diff --git a/quantecon/tests/test_graph_tools.py b/quantecon/tests/test_graph_tools.py
index 00e20b526..222c27ef9 100644
--- a/quantecon/tests/test_graph_tools.py
+++ b/quantecon/tests/test_graph_tools.py
@@ -134,7 +134,7 @@ def setup_method(self):
         for graph_dict in self.graphs.graph_dicts:
             try:
                 weighted = graph_dict['weighted']
-            except:
+            except KeyError:
                 weighted = False
             graph_dict['g'] = DiGraph(graph_dict['A'], weighted=weighted)
 
diff --git a/quantecon/tests/test_quadsum.py b/quantecon/tests/test_quadsum.py
index 60011b6c6..2843144bd 100644
--- a/quantecon/tests/test_quadsum.py
+++ b/quantecon/tests/test_quadsum.py
@@ -53,11 +53,3 @@ def test_m_matsum():
         summedval = summedval + a**i * b * a.T**i
 
     assert_allclose(retval, summedval, atol=1e-5, rtol=0)
-
-
-
-if __name__ == '__main__':
-    test_simplesum()
-    test_identitysum()
-    test_m_simplesum()
-    test_m_identitysum
diff --git a/quantecon/util/notebooks.py b/quantecon/util/notebooks.py
index 37b0f1bf4..5dc60e51d 100644
--- a/quantecon/util/notebooks.py
+++ b/quantecon/util/notebooks.py
@@ -86,7 +86,7 @@ def fetch_nb_dependencies(files, repo=REPO, raw=RAW, branch=BRANCH, folder=FOLDE
     import requests
 
     #-Generate Common Data Structure-#
-    if type(files) == list:
+    if isinstance(files, list):
         files = {"" : files}
 
     status = []
diff --git a/quantecon/util/timing.py b/quantecon/util/timing.py
index f415e23c8..83c125051 100644
--- a/quantecon/util/timing.py
+++ b/quantecon/util/timing.py
@@ -247,7 +247,7 @@ def __enter__(self):
         self._start_time = time.time()
         return self
         
-    def __exit__(self, exc_type, exc_val, exc_tb):
+    def __exit__(self, *exc_info):
         end_time = time.time()
         self.elapsed = end_time - self._start_time