Python example: type hints

# primitives

def func(a: int, b: float) -> str:

  a: str = f"{a}, {b}"

  return a

# complex types and collections

from typing import List

​

class Person:

  name: str

  age: int

​

def get_names(people: List[Person]) -> List[str]:

  return [person.name for person in people]

# map/dict

from typing import Dict

​

def get_counts(words: List[str]) -> Dict[str, int]:

  counts = {}

  for word in words:

    if word in counts:

      counts[word] += 1

    else:

      counts[word] = 1

  return counts

​