Python触ってて出てきたwithがなんなのか分からなかったので調べた

contextmanager_example.py

from contextlib import contextmanager

@contextmanager
def hoge():
    try:
        print("start")    
        yield "Hello, "
    finally:
        print("end")

with hoge() as msg:
    print(msg + "World!") #=> Hello, World!

example_by.rb

def hoge
  puts("start")
  yield "Hello, "
ensure
  puts("end")
end

hoge do |msg|
  puts(msg + "World!") #=> Hello, World!
end