fix: replace bare except with except Exception (3 files)

[harshadkhetpal]

Summary

Replace bare except: clauses with except Exception: across 3 files to improve error handling specificity.

Bare except: catches all exceptions including SystemExit, KeyboardInterrupt, and GeneratorExit, which should typically propagate. Since none of these sites re-raise, except Exception: is the correct replacement (PEP 8, B001).

Changes:

extension/pytree/__init__.py:

# Before
except:
# After
except Exception:

examples/models/mobilenet_v2/model.py:

# Before
            except:
# After
            except Exception:

examples/models/llama/install_requirement_helper.py (2 occurrences):

# Before
    except:
    except:
# After
    except Exception:
    except Exception:

Testing

No behavior change — style/correctness fix only. All sites are import fallbacks or error-swallowing patterns where Exception is the appropriate base class.

cc @mergennachin @iseeyuan @lucylq @helunwencser @tarun292 @kimishpatel @jackzhxng @larryliu0820 @cccclai

[pytorch-bot]

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❌ 1 Awaiting Approval, 1 New Failure, 3 Unrelated Failures

As of commit 09a9209 with merge base b9a6b84 ():

AWAITING APPROVAL - The following workflow needs approval before CI can run:

• periodic (gh)

NEW FAILURE - The following job has failed:

• Lint / lintrunner-mypy (gh)
  >>> Lint for backends/arm/test/models/stable_diffusion/stable_diffusion_module_test_configs.py:

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest-editable / macos / macos-job (gh) (trunk failure)
  export/tests/test_target_recipes.py::TestTargetRecipes::test_mv3_model
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.

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[nil-is-all]

Hi @harshadkhetpal, do resolve the errors logged by the lintrunner and let us know.