---
id: 9c7873fa-2c4e-4058-a315-cefb3c02788a
type: code_pattern
title: "When extracting a class, also move its module-level helper dependencies"
tags: [python, refactoring, code-organization, circular-imports, paper-dynasty]
importance: 0.7
confidence: 0.8
created: "2026-02-25T22:44:27.648627+00:00"
updated: "2026-02-25T22:44:41.938081+00:00"
relations:
  - target: b235f924-b532-40cd-be39-4fb765938add
    type: BUILDS_ON
    direction: incoming
    strength: 0.8
    edge_id: 45342806-cdc6-478e-aa38-4294045aafe8
---

## Pattern\nWhen extracting a class to a new file, check if any module-level helper functions are called from within the class's methods. Those helpers must move to the new file too — otherwise the new file would need to import back from the original file, re-creating a circular import.\n\n## Example (paper-dynasty/card-creation)\n`batters/models.py` received `BattingCardRatingsModel` plus 13 helper functions called by its methods:\n- `bp_singles`, `wh_singles`, `one_singles`\n- `bp_homeruns`, `triples`, `two_doubles`\n- `hit_by_pitch`, `strikeouts`\n- `flyout_a`, `flyout_bq`, `flyout_b`\n- `groundball_a`, `groundball_c`\n\nBy contrast, `pitchers/models.py` contains only `PitchingCardRatingsModel` because it had no module-level helper dependencies.\n\n## Rule\nBefore finalising a class extraction, grep the class body for any unqualified function calls and trace them back to their definition file.