Source

In the function greeting, the argument name is expected be a type of str that returns the type str

def greeting(name: str) -> str:
	return 'Hello ' + name

Types are not strongly enforced in Python

What is it

Below code is for Python 3.10+

# typing a variable
age: int = 1

# uninitialized variable can also be typed
status: int

# uninitialized can be used later
if response:
  status = 200

Built-in Types

x: int = 1
x: float = 1.0
x: bool = True
x: str = "test"
x: bytes = b"test"

# collection
x: list[int] = [1]
x: set[int] = {6, 7}

# mappings
x: dict[str, float] = {"field": 2.0}

# multiple types
x: list[int | str] = [3, 5, "test", "fun"]

# Function
def stringify(num: int) -> str:
  return str(num)

# Default value
def show(value: str, excitement: int = 10) -> None:
  print(value + "!" * excitement)