Simplify get_ffi_func (#1861)

py-polars/polars/internals/series.py

@@ -76,9 +76,8 @@ def match_dtype(value: Any, dtype: "Type[DataType]") -> Any:
 def get_ffi_func(
     name: str,
     dtype: Type["DataType"],
-    obj: Optional["Series"] = None,
-    default: Optional[Callable[[Any], Any]] = None,
-) -> Callable[..., Any]:
+    obj: "PySeries",
+) -> Optional[Callable[..., Any]]:
     """
     Dynamically obtain the proper ffi function/ method.
 
@@ -91,20 +90,15 @@ def get_ffi_func(
     dtype
         polars dtype.
     obj
-        Optional object to find the method for. If none provided globals are used.
-    default
-        default function to use if not found.
+        Object to find the method for.
 
     Returns
     -------
-    ffi function
+    ffi function, or None if not found
     """
     ffi_name = dtype_to_ffiname(dtype)
     fname = name.replace("<>", ffi_name)
-    if obj:
-        return getattr(obj, fname, default)
-    else:
-        return globals().get(fname, default)
+    return getattr(obj, fname, None)
 
 
 def wrap_s(s: "PySeries") -> "Series":
@@ -391,6 +385,8 @@ def __truediv__(self, other: Any) -> "Series":
             other = maybe_cast(other, self.dtype)
             dtype = date_like_to_physical(self.dtype)
             f = get_ffi_func("div_<>", dtype, self._s)
+            if f is None:
+                return NotImplemented
             return wrap_s(f(other))
 
         if self.dtype != physical_type:
@@ -406,6 +402,8 @@ def __floordiv__(self, other: Any) -> "Series":
         other = maybe_cast(other, self.dtype)
         dtype = date_like_to_physical(self.dtype)
         f = get_ffi_func("div_<>", dtype, self._s)
+        if f is None:
+            return NotImplemented
         if self.is_float():
             return wrap_s(f(other)).floor()
         return wrap_s(f(other))
@@ -1879,13 +1877,17 @@ def __array_ufunc__(
 
             try:
                 f = get_ffi_func("apply_ufunc_<>", dtype, self._s)
+                if f is None:
+                    return NotImplemented
                 series = f(lambda out: ufunc(*args, out=out, **kwargs))
                 return wrap_s(series)
             except TypeError:
                 # some integer to float ufuncs do not work, try on f64
                 s = self.cast(Float64)
                 args[0] = s.view(ignore_nulls=True)
                 f = get_ffi_func("apply_ufunc_<>", Float64, self._s)
+                if f is None:
+                    return NotImplemented
                 series = f(lambda out: ufunc(*args, out=out, **kwargs))
                 return wrap_s(series)