File fromFile = x.getKey();
Multimap<File, Export> m = x.getValue();
// get any ambiguities
Multimap<File, Export> ambiguitiesForFile = ambiguities.get(fromFile);
for(File toFile : m.keySet()) {
createImportEdge(
file2Module(fromFile, fileIndex), file2Module(toFile, fileIndex), m.get(toFile),
ambiguitiesForFile != null
? ambiguitiesForFile.get(toFile)
: null);