Returns the first key in the provided dictionary that has the given value.

Use dictionary.items() and next() to return the first key that has a value equal to val.


def find_key(dict, val):
  return next(key for key, value in dict.items() if value == val)


ages = {
  "Peter": 10,
  "Isabel": 11,
  "Anna": 9,
find_key(ages, 11) # "Isabel"