Replace conf['paths'] by conf.getpath('paths'

sbws/core/generate.py

@@ -59,6 +59,7 @@ def main(args, conf):
                     'ran sbws scanner recently?)')
         return
     bw_file = V3BWFile.from_arg_results(args, conf, results)
-    output = args.output or conf['paths']['v3bw_fname'].format(now_fname())
+    output = args.output or \
+        conf.getpath('paths', 'v3bw_fname').format(now_fname())
     bw_file.write(output)
     log.info('Mean bandwidth per line: %f "KiB"', bw_file.avg_bw)