tbl: base _Columns on Parented

Steve Canny · Steve Canny · commit 6b717152d95d · 2014-07-11T16:55:24.000-07:00
diff --git a/docx/table.py b/docx/table.py
@@ -51,7 +51,7 @@ def columns(self):
         """
         |_Columns| instance containing the sequence of rows in this table.
         """
-        return _Columns(self._tbl)
+        return _Columns(self._tbl, self)
 
     @lazyproperty
     def rows(self):
@@ -179,13 +179,13 @@ def _tr_lst(self):
         return self._tbl.tr_lst
 
 
-class _Columns(object):
+class _Columns(Parented):
     """
     Sequence of |_Column| instances corresponding to the columns in a table.
     Supports ``len()``, iteration and indexed access.
     """
-    def __init__(self, tbl):
-        super(_Columns, self).__init__()
+    def __init__(self, tbl, parent):
+        super(_Columns, self).__init__(parent)
         self._tbl = tbl
 
     def __getitem__(self, idx):
diff --git a/tests/test_table.py b/tests/test_table.py
@@ -271,7 +271,7 @@ def it_raises_on_indexed_access_out_of_range(self, columns_fixture):
     def columns_fixture(self):
         column_count = 2
         tbl = _tbl_bldr(rows=2, cols=column_count).element
-        columns = _Columns(tbl)
+        columns = _Columns(tbl, None)
         return columns, column_count
 
 
