diff --git a/python/cudf/cudf/_lib/pylibcudf/column.pyx b/python/cudf/cudf/_lib/pylibcudf/column.pyx
index c7454560c01..cb96c1d9fce 100644
--- a/python/cudf/cudf/_lib/pylibcudf/column.pyx
+++ b/python/cudf/cudf/_lib/pylibcudf/column.pyx
@@ -180,9 +180,9 @@ cdef class Column:
 
         Parameters
         ----------
-        mask
+        mask : gpumemoryview
             New mask (or None to unset the mask)
-        null_count
+        null_count : int
             New null count. If this is incorrect, bad things happen.
 
         Returns
diff --git a/python/cudf/cudf/_lib/pylibcudf/transform.pyx b/python/cudf/cudf/_lib/pylibcudf/transform.pyx
index bf18c6a91a5..a734e71b820 100644
--- a/python/cudf/cudf/_lib/pylibcudf/transform.pyx
+++ b/python/cudf/cudf/_lib/pylibcudf/transform.pyx
@@ -17,7 +17,7 @@ cpdef tuple[gpumemoryview, int] nans_to_nulls(Column input):
 
     Parameters
     ----------
-    input
+    input : Column
         Column to produce new mask from.
 
     Returns