Tiny 'shelve'-like database with concurrency support
Description
PickleShare - a small ‘shelve’ like data store with concurrency support.
Like shelve, a PickleShareDB object acts like a normal dictionary.
Unlike shelve, many processes can access the database simultaneously.
Changing a value in database is immediately visible to other processes
accessing the same database.
Concurrency is possible because the values are stored in separate files.
Hence the “database” is a directory where all files are governed
by PickleShare.
