Hi there! Due to certain limitations, we are trying to install the graphtool version 2.7 on a redhat distribution. After a lot of fidling around, we have been able to make the functions we need work, except for the find_edge_range function. The following simple example demonstrates the problem: from graph_tool.all import * g = Graph() v1, v2 = g.add_vertex(), g.add_vertex() e1,e2 = g.add_edge(v1,v2), g.add_edge(v2,v1) res = g.new_edge_property("double") res[e1] = 0.1 res[e2] = 12. eList = find_edge_range(g,res, [0.0, 1.]) This causes the following issue: Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/graph_tool/util/__init__.py", line 84, in find_edge_range convert = converter(prop.value_type()) NameError: global name 'converter' is not defined Unfortunately, I have not found a way to see the actual code, where this error arises. Was this a problem in that particular version? What do I need to do to find the code where this issue arises? The following python loop is able to reproduce the desired behavior, but it is way too slow: eList = [] for e in g.edges(): if res[e] <= eps and res[e] >= 0.0: eList.append(e) Is there a more efficient way to do this, if I cannot make "find_edge_range" work? Looking forward to hearing from you. All the best, Alex