Use advanced container types for various needs.
Source Code
from collections import defaultdict, namedtuple, Counter, deque
# defaultdict: returns a default value for missing keys
dd = defaultdict(int)
# namedtuple: lightweight object type
Point = namedtuple('Point', ['x', 'y'])
# Counter: dict subclass for counting hashable objects
cnt = Counter()
# deque: list-like container with fast appends and pops on either end
dq = deque()