Maintain configuration in a single, consistent way across the codebase: - **Use explicit defaults + safe fallbacks:** If function parameters accept `None`, resolve them via config defaults (and document why). Prefer provider-specific keys so changing one provider doesn’t silently alter another. - **Avoid duplicated “source of truth”:** If base URLs / endpoints / constants are repeated across modules, centralize them (e.g., one dict/module imported everywhere) rather than copying per file. - **Stay aligned with shared validation:** When configs are meant to represent “valid” values (e.g., model names), mirror the upstream/default config + validators. If you need to change allowed values, do it via the upstream/shared change—not by diverging locally. Example pattern (provider-specific defaults + None fallback): ```py def get_global_news(curr_date, look_back_days: int | None = 7, limit: int | None = 50) -> dict: # Resolve None via provider-specific config keys if look_back_days is None: look_back_days = DEFAULT_CONFIG.get("global_news_look_back_days", 7) if limit is None: # Keep Alpha Vantage historical default separate from other providers limit = DEFAULT_CONFIG.get("av_global_news_limit", 50) ... ``` Follow-up actions when issues are found: - If you add a new provider, **update the centralized config mapping** once (and remove/avoid duplicating URLs elsewhere). - If you adjust valid model/provider values, **open an upstream-wide PR** so validators/defaults stay consistent.