BUG: Fix to GH34422 SeriesGroupBy works only with 'func' now

pandas/core/groupby/generic.py

@@ -234,9 +234,16 @@ def aggregate(
         relabeling = func is None
         columns = None
         no_arg_message = "Must provide 'func' or named aggregation **kwargs."
+        tuple_given_message = "func is expected but recieved {} in **kwargs."
         if relabeling:
             columns = list(kwargs)
-            func = [kwargs[col] for col in columns]
+            func = []
+            for col in columns:
+                if isinstance(kwargs[col], (list, tuple)):
+                    raise TypeError(
+                        tuple_given_message.format(type(kwargs[col]).__name__)
+                    )
+                func.append(kwargs[col])
             kwargs = {}
             if not columns:
                 raise TypeError(no_arg_message)

pandas/tests/groupby/aggregate/test_aggregate.py

@@ -511,6 +511,21 @@ def test_mangled(self):
         expected = pd.DataFrame({"a": [0, 0], "b": [1, 1]})
         tm.assert_frame_equal(result, expected)
 
+    @pytest.mark.parametrize(
+        "inp",
+        [
+            pd.NamedAgg(column="anything", aggfunc="min"),
+            ("anything", "min"),
+            ["anything", "min"],
+        ],
+    )
+    def test_named_agg_nametuple(self, inp):
+        # GH34422
+        s = pd.Series([1, 1, 2, 2, 3, 3, 4, 5])
+        msg = "func is expected but recieved {}".format(type(inp).__name__)
+        with pytest.raises(TypeError, match=msg):
+            s.groupby(s.values).agg(a=inp)
+
 
 class TestNamedAggregationDataFrame:
     def test_agg_relabel(self):