Fix discoverability of submodules inside pd.util (#17215)

Fixes: #17166 

This PR fixes the discoverability of the submodules of attributes and modules inside `pd.util`. Somehow `importlib.import_module("pandas.util").__dict__` doesn't display submodules and only root level attributes.

Authors:
  - GALI PREM SAGAR (https://github.com/galipremsagar)

Approvers:
  - Matthew Murray (https://github.com/Matt711)

URL: #17215

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

@@ -75,13 +75,27 @@ def _pandas_util_dir():
     # In pandas 2.0, pandas.util contains public APIs under
     # __getattr__ but no __dir__ to find them
     # https://github.com/pandas-dev/pandas/blob/2.2.x/pandas/util/__init__.py
-    return list(importlib.import_module("pandas.util").__dict__.keys()) + [
-        "hash_array",
-        "hash_pandas_object",
-        "Appender",
-        "Substitution",
-        "cache_readonly",
-    ]
+    res = list(
+        set(
+            list(importlib.import_module("pandas.util").__dict__.keys())
+            + [
+                "Appender",
+                "Substitution",
+                "_exceptions",
+                "_print_versions",
+                "cache_readonly",
+                "hash_array",
+                "hash_pandas_object",
+                "version",
+                "_tester",
+                "_validators",
+                "_decorators",
+            ]
+        )
+    )
+    if cudf.core._compat.PANDAS_GE_220:
+        res.append("capitalize_first_letter")
+    return res
 
 
 pd.util.__dir__ = _pandas_util_dir

python/cudf/cudf_pandas_tests/test_cudf_pandas.py

@@ -1759,3 +1759,21 @@ def test_fallback_raises_error(monkeypatch):
         monkeycontext.setenv("CUDF_PANDAS_FAIL_ON_FALLBACK", "True")
         with pytest.raises(ProxyFallbackError):
             pd.Series(range(2)).astype(object)
+
+
+@pytest.mark.parametrize(
+    "attrs",
+    [
+        "_exceptions",
+        "version",
+        "_print_versions",
+        "capitalize_first_letter",
+        "_validators",
+        "_decorators",
+    ],
+)
+def test_cudf_pandas_util_version(attrs):
+    if not PANDAS_GE_220 and attrs == "capitalize_first_letter":
+        assert not hasattr(pd.util, attrs)
+    else:
+        assert hasattr(pd.util, attrs)