variables.py

# raw types are immutable variables

x = 1
def change(x):
  x = 2

change(x)
assert x == 1

# you can use the global statement, but it's not a good practice

def change():
  global x
  x = 2

change()
assert x == 2

# you can return the value and assign to the variable, it's better than global statement

def change(x):
  x = 2
  return x

x = change(x)
assert x == 2


# Immutable variables
# lists, sets, dicts and collections in general are mutable vars

itens = ["sword", "shield"]
def change(itens):
  itens.append("bow")
  
change(itens)
assert itens == ["sword", "shield", "bow"]