If you are just trying to serialize a list to disk for later use by the same python app, you should be pickleing the list --> https://docs.python.org/3/library/pickle.html
```
import pickle
with open('outfile', 'wb') as fp:
pickle.dump(itemlist, fp)
```
To read it back:
```
with open ('outfile', 'rb') as fp:
itemlist = pickle.load(fp)
```