defaultdict
code: python
from collections import defaultdict
'''
{
<user>: {
'login': set(<session_ids>)
'logout': set(<session_ids>)
}
}
'''
d = defaultdict(lambda: {
'login': set(),
'logout': set()
})
print(d'bob''login') # set()
'''
{
<path>: {
<status_code>: <count>
}
}
'''
d = defaultdict(lambda: defaultdict(int))
d'/foo''400' += 1