Are there any tools or strategies for debugging a nipype workflow that yields a “not a DAG” error? Before making a change, the workflow was fine, and I created a graph of the program flow. My change should not have introduced a DAG. The overall code is very complicated, but even going line by line, I’m not seeing the issue. Could it have something to do with where in the workflow setup nodes are connected? I thought wf.connect(a,b) followed by wf.connect(b,c) was just as good if those two lines were reversed in the wf setup.