```python
from typing import Optional, List, Tuple

def function(param1: Optional[int], param2: List[int]):
     print(param1, param2)

>>> function(None, [12, 45, 1])
#None [12, 45, 1]
# For this example, param1 had an input of None, while 
# param2 had a parameter of type List inputted. 
# The function's output reflects this.

>>> function(12, [1, 2])
#12 [1,2]
# For this example, param1 had an input of type int, while 
# param2 had a parameter of type List inputted. 
# The function's output reflects this.
```
Type annotations made for each parameter will return a TypeError if the parameter is not of the correct type.


Typing Example

Install the `typing` module from a terminal:

```bash
pip install typing
```

Then import the module in the Python file:

```python
import typing
```

Installing and Importing Typing

Python's `typing` module defines standard notation for function and variable type annotations. These annotations make intended types explicit, improving code readability and providing a consistent way to document code.

California Polytechnic State University, San Luis Obispo

Google

In Python, function parameters refer to the variables that are listed within a function definition. For example, in the function rotate(x, y), the parameters are x and y.

Function Parameters in Python

Functions in Python can have optional parameters. Functions with optional parameters can be called with or without passing an argument through the optional parameters. If no argument is provided, the default value will be passed through the parameter. The default value must be defined with an = sign in the function header. For example, in the function rotate(x, y = 3), y is an optional parameter with a default value of 3.

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