add check if other is Series

Author: natmokval

pandas/core/series.py

@@ -6662,19 +6662,20 @@ def _logical_method(self, other, op):
         return self._construct_result(res_values, name=res_name, other=other)
 
     def _arith_method(self, other, op):
-        if (
-            isinstance(self.index, MultiIndex)
-            and isinstance(other.index, MultiIndex)
-            and self.index.names != other.index.names
-        ):
-            # GH#25891
-            warnings.warn(
-                "The silent alignment on arithmetic operations between "
-                "'Series' with non-aligned MultiIndexes will be removed "
-                "in a future version, please use aligned MultiIndexes.",
-                Pandas4Warning,
-                stacklevel=find_stack_level(),
-            )
+        if isinstance(other, Series):
+            if (
+                isinstance(self.index, MultiIndex)
+                and isinstance(other.index, MultiIndex)
+                and self.index.names != other.index.names
+            ):
+                # GH#25891
+                warnings.warn(
+                    "The silent alignment on arithmetic operations between "
+                    "'Series' with non-aligned MultiIndexes will be removed "
+                    "in a future version, please align MultiIndexes.",
+                    Pandas4Warning,
+                    stacklevel=find_stack_level(),
+                )
 
         self, other = self._align_for_op(other)
         return base.IndexOpsMixin._arith_method(self, other, op)