Add BaseOffset as a final proxy type to pass instancechecks for offsets against BaseOffset

python/cudf/cudf/pandas/_wrappers/pandas.py

@@ -1036,6 +1036,15 @@ def _df_query_method(self, *args, local_dict=None, global_dict=None, **kwargs):
     additional_attributes={"__hash__": _FastSlowAttribute("__hash__")},
 )
 
+BaseOffset = make_final_proxy_type(
+    "BaseOffset",
+    _Unusable,
+    pd.offsets.BaseOffset,
+    fast_to_slow=_Unusable(),
+    slow_to_fast=_Unusable(),
+    additional_attributes={"__hash__": _FastSlowAttribute("__hash__")},
+)
+
 Day = make_final_proxy_type(
     "Day",
     _Unusable,

python/cudf/cudf_pandas_tests/test_cudf_pandas.py

@@ -1233,3 +1233,8 @@ def test_concat_fast():
 def test_func_namespace():
     # note: this test is sensitive to Pandas' internal module layout
     assert xpd.concat is xpd.core.reshape.concat.concat
+
+
+def test_isinstance_base_offset():
+    offset = xpd.tseries.frequencies.to_offset("1s")
+    assert isinstance(offset, xpd.tseries.offsets.BaseOffset)