funcs.py

def foo(stuff):
  return stuff
  
def bar(stuff):
  return 3 * stuff

def f(func, stuff):
  return 2 * func(stuff)

f(bar, 5) # => 

stuff.py

nums = [1,2,3,4,5]
nums.sort()

def div_yield(ticker):
  # Magic shit here
  return div_yield_for_ticker
  
tickers = ["foo", "bar", "aapl", "msft", "goog", "baz"]
alphabet_sorted_tickers = tickers.sorted()
div_yield_tickers = tickers.sorted(key=div_yield)