Fix find_spec for old finders that don't implement it.

site-packages/_numba_cuda_redirector.py

@@ -67,9 +67,15 @@ def find_spec(self, name, path, target=None):
             oot_path = [p.replace(self.numba_path, self.numba_cuda_path)
                         for p in path]
             for finder in sys.meta_path:
-                spec = finder.find_spec(name, oot_path, target)
-                if spec is not None:
-                    return spec
+                try:
+                    spec = finder.find_spec(name, oot_path, target)
+                except AttributeError:
+                    # Finders written to a pre-Python 3.4 spec for finders will not
+                    # implement find_spec. We can skip those altogether.
+                    continue
+                else:
+                    if spec is not None:
+                        return spec
 
 
 finder = NumbaCudaFinder()