fix(cpr): rename open param to open_ so the accessor resolves it

The cpr `open` input parameter was named `open` (bare) instead of the
`open_` convention used across the codebase. The DataFrame accessor's
generic column mapper only maps the `open_` param to the `open` column,
so `df.ta.cpr()` never fetched open prices: cpr() received open=None,
returned None, and the accessor fell back to the unchanged input frame
(the 11 CPR columns collapsed to the original OHLC 4). Direct positional
calls were unaffected, which is why the existing tests passed.

Rename the parameter to `open_`, regenerate core.pyi (the accessor stub
no longer carries a stray `open` param), and add an accessor regression
test asserting CPR_PIVOT is present in the result.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -34,6 +34,7 @@ Format: [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 * **Unused hard dependencies**: `scipy`, `scikit-learn`, and `statsmodels` dropped from `[project.dependencies]` — nothing in the package imports them anymore. `_linear_regression_sklearn()` removed (see Changed). Stale `Imports` probes pruned (`backtrader`, `matplotlib`, `mplfinance`, `numba`, `scipy`, `sklearn`, `statsmodels`, `vectorbt`, `yaml`); numba acceleration is unaffected (`utils/_njit.py` self-detects numba).
 
 ### Fixed
+* **`cpr` accessor path silently returned the input frame**: the `open` input parameter was named `open` (bare) instead of the `open_` convention. The DataFrame accessor's generic column mapper only maps the `open_` param to the `open` column, so `df.ta.cpr()` never fetched open prices, `cpr()` returned `None`, and the accessor fell back to the unchanged input DataFrame. Renamed the parameter to `open_`; positional calls are unaffected.
 * **Cross-package indicator imports**: A submodule import could overwrite a re-exported function of the same name on the parent package (e.g. `from pandas_ta_classic.volatility import atr` occasionally returned the `atr` *module* instead of the function). Resolved.
 * **Test-fixture regen no longer drops `cmo_14` entries** when running tests without tulipy installed. Generators now merge with existing JSON instead of overwriting.
 

pandas_ta_classic/core.pyi

@@ -564,7 +564,6 @@ class AnalysisIndicators:
     ) -> Optional[DataFrame]: ...
     def cpr(
         self,
-        open: Series,
         method: str = 'classic',
         timeframe: str = 'daily',
         interval: Optional[str] = None,

pandas_ta_classic/trend/cpr.py

@@ -71,7 +71,7 @@ def _cpr_build_dataframe(pivot_result, levels, width_analysis, price_position, v
 
 
 def cpr(
-    open: Series,
+    open_: Series,
     high: Series,
     low: Series,
     close: Series,
@@ -101,17 +101,17 @@ def cpr(
         levels = "standard"
 
     length = 1  # For verify_series
-    open = verify_series(open, length)
+    open_ = verify_series(open_, length)
     high = verify_series(high, length)
     low = verify_series(low, length)
     close = verify_series(close, length)
     offset = get_offset(offset)
 
-    if _any_none(open, high, low, close):
+    if _any_none(open_, high, low, close):
         return None
 
     # Prepare DataFrame for OHLCV processing
-    ohlcv_df = DataFrame({"open": open, "high": high, "low": low, "close": close})
+    ohlcv_df = DataFrame({"open": open_, "high": high, "low": low, "close": close})
     if volume is not None:
         ohlcv_df["volume"] = volume
 
@@ -383,7 +383,7 @@ Calculation:
         S2 = Pivot - (H - L)
 
 Args:
-    open (pd.Series): Series of 'open's
+    open_ (pd.Series): Series of 'open's
     high (pd.Series): Series of 'high's
     low (pd.Series): Series of 'low's
     close (pd.Series): Series of 'close's

tests/test_ext_indicator_trend.py

@@ -53,6 +53,14 @@ class TestTrendExtension(TestCase):
         self.assertIsInstance(self.data, DataFrame)
         self.assertEqual(list(self.data.columns[-2:]), ["CKSPl_10_1_9", "CKSPs_10_1_9"])
 
+    def test_cpr_ext(self):
+        # Regression: the generic accessor maps the open_ param to the 'open'
+        # column. A bare 'open' param made df.ta.cpr() silently return the
+        # unchanged input frame instead of computing CPR.
+        result = self.data.ta.cpr()
+        self.assertIsInstance(result, DataFrame)
+        self.assertIn("CPR_PIVOT", result.columns)
+
     def test_decay_ext(self):
         self.data.ta.decay(append=True)
         self.assertIsInstance(self.data, DataFrame)