From 49ef964f8a260e8318ee8d143269e2c2532f7517 Mon Sep 17 00:00:00 2001
From: deanm0000 <37878412+deanm0000@users.noreply.github.com>
Date: Sun, 28 Apr 2024 08:35:13 -0400
Subject: [PATCH] fix(python): Change recognition of numba ufunc (#15916)

---
 py-polars/polars/expr/expr.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/py-polars/polars/expr/expr.py b/py-polars/polars/expr/expr.py
index 3e0dc65d83ae..70a1f75d3808 100644
--- a/py-polars/polars/expr/expr.py
+++ b/py-polars/polars/expr/expr.py
@@ -293,7 +293,8 @@ def __array_ufunc__(
         if method != "__call__":
             msg = f"Only call is implemented not {method}"
             raise NotImplementedError(msg)
-        is_custom_ufunc = ufunc.__class__ != np.ufunc
+        # Numpy/Scipy ufuncs have signature None but numba signatures always exists.
+        is_custom_ufunc = getattr(ufunc, "signature") is not None  # noqa: B009
         num_expr = sum(isinstance(inp, Expr) for inp in inputs)
         exprs = [
             (inp, Expr, i) if isinstance(inp, Expr) else (inp, None, i)