Add DataFrame.insert_columns

spec/API_specification/dataframe_api/dataframe_object.py

@@ -180,9 +180,9 @@ def get_rows_by_mask(self, mask: Column[Bool]) -> DataFrame:
         """
         ...
 
-    def insert_column(self, column: Column[Any]) -> DataFrame:
+    def insert_columns(self, columns: Column[Any] | Sequence[Column[Any]]) -> DataFrame:
         """
-        Insert column into DataFrame at rightmost location.
+        Insert column(s) into DataFrame at rightmost location.
 
         The column's name will be used as the label in the resulting dataframe.
         To insert the column with a different name, combine with `Column.rename`,
@@ -203,9 +203,22 @@ def insert_column(self, column: Column[Any]) -> DataFrame:
             df = df.insert_column(new_column.rename('a_plus_1'))
             df = df.get_columns_by_name(new_column_names)
 
+        If inserting multiple columns, they must be indepedent.
+        For example, 
+
+        .. code-block:: python
+
+            new_column_1 = df.get_column_by_name('a').rename('b')
+            new_column_2 = (new_column_1 + 2).rename('c')
+            df.insert_columns([new_column_1, new_column_2])
+
+        is not allowed, as `new_column_2` depends on `new_column_1`.
+
         Parameters
         ----------
-        column : Column
+        columns : Column | Sequence[Column]
+            Column(s) to insert. Must be independent of each other, so that insertion
+            can happen in parallel in some implementations.
         """
         ...