fix a bug with List

src/jflow/workflow.py

@@ -264,10 +264,14 @@ class Workflow(threading.Thread):
                     if param.type.__name__ == "inputfile" or param.type.__name__ == "browsefile":
                         for path in path2test:
                             default_vals.append(os.path.join(self.jflow_config_reader.get_tmp_directory(), (path)))
-                    self.__getattribute__(param.name).extend(default_vals)
+                    self.__setattr__(param.name, default_vals)
+                else:
+                    self.__setattr__(param.name, [])
             elif param.__class__ ==  ParameterList:
                 if args[param.name]:
-                    self.__getattribute__(param.name).extend(args[param.name])
+                    self.__setattr__(param.name, args[param.name])
+                else:
+                    self.__setattr__(param.name, [])
             elif param.__class__ == MultiParameter:
                 sub_args = {}
                 for sarg in args[param.name]:
@@ -278,6 +282,7 @@ class Workflow(threading.Thread):
                     else:
                         self.__getattribute__(param.name)[sub_param.name] = sub_param.default
             elif param.__class__ == MultiParameterList:
+                final_vals = []
                 for sargs in args[param.name]:
                     sub_args, final_sub_args = {}, {}
                     for sarg in sargs:
@@ -287,7 +292,8 @@ class Workflow(threading.Thread):
                             final_sub_args[sub_param.name] = sub_args[sub_param.flag]
                         else:
                             final_sub_args[sub_param.name] = sub_param.default
-                    self.__getattribute__(param.name).append(final_sub_args)
+                    final_vals.append(final_sub_args)
+                self.__setattr__(param.name, final_vals)
     
     def get_execution_graph(self):
         graph = Graph()