diff --git a/test/python/analyse_block_structure_from_gf2.py b/test/python/analyse_block_structure_from_gf2.py
index 25806815..c0faeb06 100644
--- a/test/python/analyse_block_structure_from_gf2.py
+++ b/test/python/analyse_block_structure_from_gf2.py
@@ -54,11 +54,11 @@ def get_random_transformation(dim):
 assert_block_gfs_are_close(G_new[0], G_new_symm)
 
 
-assert SK.gf_struct_sumk == [[('ud', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9])], [('ud', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9])]],\
+assert SK.gf_struct_sumk == [[('ud', 10)], [('ud', 10)]],\
     "wrong gf_struct_sumk"
 for i in range(5):
     assert 'ud_{}'.format(i) in SK.gf_struct_solver[0], "missing block"
-    assert SK.gf_struct_solver[0]['ud_{}'.format(i)] == list(range(2)), "wrong block size"
+    assert SK.gf_struct_solver[0]['ud_{}'.format(i)] == 2, "wrong block size"
 for i in range(10):
     assert SK.sumk_to_solver[0]['ud',i] == ('ud_{}'.format(i//2), i%2), "wrong mapping"
 
@@ -98,11 +98,11 @@ def get_delta_from_mesh(mesh):
 SK.symm_deg_gf(G_new_symm, 0)
 assert_block_gfs_are_close(G_new[0], G_new_symm)
 
-assert SK.gf_struct_sumk == [[('ud', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9])], [('ud', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9])]],\
+assert SK.gf_struct_sumk == [[('ud', 10)], [('ud', 10)]],\
     "wrong gf_struct_sumk"
 for i in range(5):
     assert 'ud_{}'.format(i) in SK.gf_struct_solver[0], "missing block"
-    assert SK.gf_struct_solver[0]['ud_{}'.format(i)] == list(range(2)), "wrong block size"
+    assert SK.gf_struct_solver[0]['ud_{}'.format(i)] == 2, "wrong block size"
 for i in range(10):
     assert SK.sumk_to_solver[0]['ud',i] == ('ud_{}'.format(i//2), i%2), "wrong mapping"
 
diff --git a/test/python/basis_transformation.py b/test/python/basis_transformation.py
index 6905cdf5..a180b999 100644
--- a/test/python/basis_transformation.py
+++ b/test/python/basis_transformation.py
@@ -1,3 +1,4 @@
+from tkinter import W
 from triqs.utility.comparison_tests import *
 from triqs_dft_tools.sumk_dft import *
 import numpy as np
@@ -92,7 +93,7 @@ def call_diagonalize(SK):
 H3 = BS.convert_operator(h_int_slater(spin_names=['up','down'], orb_names=[0,1,2], U_matrix=U3x3, off_diag=True))
 for op in H3:
     for c_op in op[0]:
-        assert(BS.gf_struct_solver_dict[0][c_op[1][0]][c_op[1][1]] is not None) # This crashes with a key error if the operator structure is not the solver structure
+        assert(BS.solver_to_sumk[0][(c_op[1][0], c_op[1][1])] is not None) # This crashes with a key error if the operator structure is not the solver structure
 
 U_trafod = transform_U_matrix(U3x3, BS.transformation[0]['up'].conjugate()) # The notorious .conjugate()
 H4 = h_int_slater(spin_names=['up','down'], orb_names=range(3), U_matrix=U_trafod, map_operator_structure=BS.sumk_to_solver[0])
diff --git a/test/python/blockstructure.py b/test/python/blockstructure.py
index ed34bfe3..d902f757 100644
--- a/test/python/blockstructure.py
+++ b/test/python/blockstructure.py
@@ -174,11 +174,9 @@ def cmp(a, b, precision=1.e-15):
 
 # check full_structure
 full = BlockStructure.full_structure(
-    [{'up_0': [0, 1], 'up_1': [0], 'down_1': [0], 'down_0': [0, 1]}], None)
+    [{'up_0': 2, 'up_1': 1, 'down_1': 1, 'down_0': 2}], None)
 
-print(original_bs.gf_struct_sumk[0])
-print(gf_struct_flatten(original_bs.gf_struct_sumk[0]))
-G_sumk = BlockGf(mesh=G1.mesh, gf_struct=gf_struct_flatten(original_bs.gf_struct_sumk[0]))
+G_sumk = BlockGf(mesh=G1.mesh, gf_struct=original_bs.gf_struct_sumk[0])
 for i in range(3):
     G_sumk['up'][i, i] << SemiCircular(1 if i < 2 else 2)
     G_sumk['down'][i, i] << SemiCircular(4 if i < 2 else 3)
@@ -204,13 +202,13 @@ def cmp(a, b, precision=1.e-15):
 assert_block_gfs_are_close(G1, G_bT)
 
 assert original_bs.gf_struct_sumk_list ==\
-    [[('up', [0, 1, 2]), ('down', [0, 1, 2])]]
+    [[('up', 3), ('down', 3)]]
 assert original_bs.gf_struct_solver_dict ==\
-    [{'up_0': [0, 1], 'up_1': [0], 'down_1': [0], 'down_0': [0, 1]}]
+    [{'up_0': 2, 'up_1': 1, 'down_1': 1, 'down_0': 2}]
 assert original_bs.gf_struct_sumk_dict ==\
-    [{'down': [0, 1, 2], 'up': [0, 1, 2]}]
+    [{'down': 3, 'up': 3}]
 assert original_bs.gf_struct_solver_list ==\
-    [[('down_0', [0, 1]), ('down_1', [0]), ('up_0', [0, 1]), ('up_1', [0])]]
+    [[('down_0', 2), ('down_1', 1), ('up_0', 2), ('up_1', 1)]]
 
 # check __eq__
 assert full == full, 'equality not correct (equal structures not equal)'