# Revision history [back]

### Stopiteration Raised

I am using gray codes to generate a set of of combinations and testing each combination for certain qualities. I have never had the code fail for any reason before this run. I kind of no idea why this would occur. There should be many more test cases. Has anyone seen G.eulerian_circuit() fail with a StopIteration before? I can post more code if needed.

Find all length 13 sets from 36 edges

Processing |                                | 4329384/2310789600
Traceback (most recent call last):
File "fold.sage.py", line 334, in <module>
planar, G = gray(flatten, all_vertex_pairs)
File "fold.sage.py", line 70, in gray
flag, planar, G = test_edges(all_vertex_pairs, s, flatten)
File "fold.sage.py", line 243, in test_edges
if G.eulerian_circuit() is False:
File "/opt/sagemath-8.6/local/lib/python2.7/site-packages/sage/graphs/generic_graph.py", line 3935, in eulerian_circuit
next_edge = next(g_edge_iter(v))
StopIteration