Implement chunks matrix transposed method

da/common.py

@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from itertools import chain
-from typing import List, Generator
+from typing import List, Generator, Self
 
 from eth2spec.eip7594.mainnet import Bytes32
 
@@ -24,7 +24,10 @@ class Row(List[Bytes32]):
 class ChunksMatrix(List[Row]):
     @property
     def columns(self) -> Generator[List[Chunk], None, None]:
-        yield from map(list, zip(*self))
+        yield from map(Row, zip(*self))
+
+    def transposed(self) -> Self:
+        return ChunksMatrix(self.columns)
 
 
 

da/test_common.py

@@ -10,3 +10,8 @@ class TestCommon(TestCase):
         expected = [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
         for c1, c2 in zip(expected, matrix.columns):
             self.assertEqual(c1, c2)
+
+    def test_chunks_matrix_transposed(self):
+        matrix = ChunksMatrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
+        expected = ChunksMatrix([[1, 4, 7], [2, 5, 8], [3, 6, 9]])
+        self.assertEqual(matrix.transposed(), expected)