`imp.find_module` goes down in flames if one tries to pass an iterator rather than a list of folders.  Firstly, the message that it produces is somewhat misleading:

   RuntimeError: sys.path must be a list of directory names

Secondly, it would be helpful if one could pass an iterator. I'm thinking in particular of the situation where one wants to import something from a large folder tree, and the module in question is likely to be found early in the search process, so that it is more efficient to explore the folder tree incrementally.