diff --git a/python/pmtiles/writer.py b/python/pmtiles/writer.py
index 185d023..a51861e 100644
--- a/python/pmtiles/writer.py
+++ b/python/pmtiles/writer.py
@@ -39,11 +39,11 @@ def make_pyramid(tile_entries,start_leaf_offset,max_dir_size=21845):
 
   for group in itertools.groupby(entries_in_leaves,key=by_parent):
     subpyramid_entries = list(group[1])
-    root = subpyramid_entries[0]
+
+    root = by_parent(subpyramid_entries[0])
     if len(packed_entries) + len(subpyramid_entries) <= max_dir_size:
-      # the first item MUST be the root of the pyramid (sorted) - but it may have multiple roots
       packed_entries.extend(subpyramid_entries)
-      packed_roots.append((root.z,root.x,root.y))
+      packed_roots.append((root[0],root[1],root[2]))
     else:
       # flush the current packed entries
 
@@ -55,7 +55,7 @@ def make_pyramid(tile_entries,start_leaf_offset,max_dir_size=21845):
 
       current_offset += 17 * len(packed_entries)
       packed_entries = subpyramid_entries
-      packed_roots = [(root.z,root.x,root.y)]
+      packed_roots = [(root[0],root[1],root[2])]
 
   # finalize the last set
   if len(packed_entries):
@@ -66,7 +66,6 @@ def make_pyramid(tile_entries,start_leaf_offset,max_dir_size=21845):
     packed_entries.sort(key=entrysort)
     leaf_dirs.append(packed_entries)
 
-  # sort root entries again?
   return (root_entries,leaf_dirs)
 
 @contextmanager
diff --git a/python/test/test_writer.py b/python/test/test_writer.py
index ae3db26..73cb275 100644
--- a/python/test/test_writer.py
+++ b/python/test/test_writer.py
@@ -60,11 +60,28 @@ class TestTilePyramid(unittest.TestCase):
         Entry(3,1,3,14,1,False)
       ]
       root_entries, leaf_dirs = make_pyramid(entries,0,7)
-      print(root_entries)
       self.assertEqual(len(root_entries),7)
       self.assertEqual(root_entries[5].y,0)
       self.assertEqual(root_entries[6].y,1)
 
+    def test_sparse_pyramid(self):
+      entries = [
+        Entry(0,0,0,0,1,False),
+        Entry(1,0,0,1,1,False),
+        Entry(1,0,1,2,1,False),
+        Entry(1,1,0,3,1,False),
+        Entry(1,1,1,4,1,False),
+        Entry(2,0,0,5,1,False),
+        Entry(3,0,0,6,1,False),
+        # Entry(2,0,1,7,1,False), make this entry missing
+        Entry(3,0,2,8,1,False)
+      ]
+      root_entries, leaf_dirs = make_pyramid(entries,0,7)
+      self.assertEqual(len(root_entries),7)
+      self.assertEqual(root_entries[6].z,2)
+      self.assertEqual(root_entries[6].x,0)
+      self.assertEqual(root_entries[6].y,1)
+
     def test_full_z7_pyramid(self):
       entries = []
       # create artificial 8 levels