Fix warnings in dataframe.py (#12369)

Contributes to #9999 and #10363.

Authors:
  - Vyas Ramasubramani (https://github.com/vyasr)

Approvers:
  - Matthew Roeschke (https://github.com/mroeschke)
  - Ashwin Srinath (https://github.com/shwina)

URL: #12369

python/cudf/cudf/core/dataframe.py

@@ -5727,6 +5727,11 @@ def _prepare_for_rowwise_op(self, method, skipna):
         common_dtype = find_common_type(filtered.dtypes)
 
         if filtered._num_columns < self._num_columns:
+            # When we update our pandas compatibility target to 2.0, pandas
+            # will stop supporting numeric_only=None and users will have to
+            # specify True/False. At that time we should also top our implicit
+            # removal of non-numeric columns here.
+            assert Version(pd.__version__) < Version("2.0.0")
             msg = (
                 "Row-wise operations currently only support int, float "
                 "and bool dtypes. Non numeric columns are ignored."

python/cudf/cudf/core/indexed_frame.py

@@ -193,7 +193,7 @@ def _get_label_range_or_mask(index, start, stop, step):
     if (
         not (start is None and stop is None)
         and type(index) is cudf.core.index.DatetimeIndex
-        and index.is_monotonic is False
+        and index.is_monotonic_increasing is False
     ):
         start = pd.to_datetime(start)
         stop = pd.to_datetime(stop)