be more intelligent when the database already exists (use the module
for the existing file, according to whichdb). Noted in the doc
strings that there doesn't seem to be a different between 'c' and 'n'.
pickle.py: new low-level persistency module (used to be called flatten)
dbmac.py: stupid dbm clone for the Mac
anydbm.py: generic dbm interface (should be extended to support gdbm)