diff --git a/.coverage b/.coverage
index 08a5539e..43833e63 100644
Binary files a/.coverage and b/.coverage differ
diff --git a/check_completeness.py b/check_completeness.py
index c7feaf3e..d1aa3a5f 100644
--- a/check_completeness.py
+++ b/check_completeness.py
@@ -47,9 +47,6 @@
 # namespace
 exclude = {
     "Mapping",
-    "Column",
-    "DataFrame",
-    "GroupBy",
     "column_object",
     "dataframe_object",
     "groupby_object",
diff --git a/dataframe_api_compat/pandas_standard/__init__.py b/dataframe_api_compat/pandas_standard/__init__.py
index a298e529..d8519486 100644
--- a/dataframe_api_compat/pandas_standard/__init__.py
+++ b/dataframe_api_compat/pandas_standard/__init__.py
@@ -2,6 +2,7 @@
 from dataframe_api_compat.pandas_standard.pandas_standard import (
     PandasDataFrame,
     PandasColumn,
+    PandasGroupBy,
 )
 import pandas as pd
 
@@ -10,6 +11,10 @@
     Sequence,
 )
 
+Column = PandasColumn
+DataFrame = PandasDataFrame
+GroupBy = PandasGroupBy
+
 
 class Int64:
     ...
diff --git a/dataframe_api_compat/polars_standard/__init__.py b/dataframe_api_compat/polars_standard/__init__.py
index 62252977..cddd7640 100644
--- a/dataframe_api_compat/polars_standard/__init__.py
+++ b/dataframe_api_compat/polars_standard/__init__.py
@@ -2,11 +2,16 @@
 from dataframe_api_compat.polars_standard.polars_standard import (
     PolarsDataFrame,
     PolarsColumn,
+    PolarsGroupBy,
 )
 
 import polars as pl
 from typing import Any, Sequence
 
+Column = PolarsColumn
+DataFrame = PolarsDataFrame
+GroupBy = PolarsGroupBy
+
 
 class Int64:
     ...
diff --git a/t.py b/t.py
index 2c59fe3e..c57bb49f 100644
--- a/t.py
+++ b/t.py
@@ -1,11 +1,29 @@
+import pandas as pd
 import polars as pl
-from datetime import date
+from typing import Any
+import dataframe_api_compat
 
-df = pl.DataFrame(
-    {
-        "date": pl.date_range(date(2020, 10, 30), date(2021, 6, 1), eager=True),
-    }
-)
-df = df.with_columns(values=pl.arange(0, len(df)))
 
-print(df.groupby_dynamic("date", every="3mo").agg(pl.col("values").sum()))
+def convert_to_standard_compliant_dataframe(df: pd.DataFrame | pl.DataFrame) -> Any:
+    # todo: type return
+    if isinstance(df, pd.DataFrame):
+        return (
+            dataframe_api_compat.pandas_standard.convert_to_standard_compliant_dataframe(
+                df
+            )
+        )
+    elif isinstance(df, pl.DataFrame):
+        return (
+            dataframe_api_compat.polars_standard.convert_to_standard_compliant_dataframe(
+                df
+            )
+        )
+    else:
+        raise AssertionError(f"Got unexpected type: {type(df)}")
+
+
+dfpd = pd.DataFrame({"a": [1, 2, 3]})
+dfpl = pl.DataFrame({"a": [1, 2, 3]})
+
+dfpd = convert_to_standard_compliant_dataframe(dfpd)
+dfpl = convert_to_standard_compliant_dataframe(dfpl)