Update src/fast_array_utils/stats/_mean_var.py

Co-authored-by: Philipp A. <flying-sheep@web.de>

Author: amalia-k510

src/fast_array_utils/stats/_mean_var.py

@@ -36,15 +36,11 @@ def mean_var_(
     from . import mean
 
     if isinstance(x, np.ndarray | types.CSBase):
-        float64 = np.float64
+        xp = np
     else:
         import array_api_compat
 
-        if array_api_compat.is_array_api_obj(x):
-            xp = array_api_compat.array_namespace(x)
-            float64 = xp.float64
-        else:
-            float64 = np.float64
+        xp = array_api_compat.array_namespace(x) if array_api_compat.is_array_api_obj(x) else np
 
     if axis is not None and isinstance(x, types.CSBase):
         mean_, var = _sparse_mean_var(x, axis=axis)