[Python] shove does not store data as expected

Dear all,
I'm trying to use the shove module (http://pypi.python.org/pypi/shove)
for a simple script. The script read a CSV file ad store the data.
When I check the content of the "store" object (instance of Shove)
*before* I close it, the data are all there but when I close and re-
open it some data are lost. How it is possible? There is something
wrong in my code or I didn't understand how shove works?

Thanks in advance.

Here is a sample of my code:

DBNAME = "file://store.db"

csv_file ="test.csv"
cities = csv.reader(open(csv_file), delimiter=";")
store = Shove(DBNAME, compress=True)
for city,region,code in cities:
entry_list = store.setdefault(region, [])
data = 'just a sample'
entry = {city:data}
entry_list.append(entry)

print "----Before closing----"
for k,v in store.iteritems():
print "Key->", k
print "Value->", v
print "----"
store.close()

store = Shove(DBNAME, compress=True)
print "----After closing and re-opening----"
for k,v in store.iteritems():
print "Key->", k
print "Value->", v
print "----"

Here is the output

----Before closing----
Key-> Marche
Value-> [{'Ancona': 'just a sample'}, {'Ascoli Piceno': 'just a
sample'}]
Key-> Piemonte
Value-> [{'Alessandria': 'just a sample'}, {'Asti': 'just a sample'}]
Key-> Puglia
Value-> [{'Bari': 'just a sample'}, {'Barletta-Andria-Trani': 'just a
sample'}]
Key-> Valle d'Aosta
Value-> [{'Aosta': 'just a sample'}]
----
----After closing and re-opening----
Key-> Marche
Value-> [{'Ancona': 'just a sample'}]
Key-> Piemonte
Value-> [{'Alessandria': 'just a sample'}]
Key-> Puglia
Value-> [{'Bari': 'just a sample'}, {'Barletta-Andria-Trani': 'just a
sample'}]
Key-> Valle d'Aosta
Value-> [{'Aosta': 'just a sample'}]
----

Here is the content of the CSV file:

Alessandria;Piemonte;AL
Ancona;Marche;AN
Aosta;Valle d'Aosta;AO
Ascoli Piceno;Marche;AP
Asti;Piemonte;AT
Bari;Puglia;BA
Barletta-Andria-Trani;Puglia;BT