What is the need of 'or default' in this python code?

Question

Here is the code all_jokes is a dictionary that has some categories mapped to jokes.

def select_joke(category):
    jokes = all_jokes[category or 'default']
    shuffle(jokes)
    return jokes[0]

Answer 1

Returns the value of the default key in the all_jokes dict if the value of category wasn't truthy:

from random import shuffle

all_jokes = {
    'joke1': ['This is joke1'],
    'joke2': ['This is joke2'],
    'default': ['This is default joke']
}

def select_joke(category):
    jokes = all_jokes[category or 'default']
    shuffle(jokes)
    return jokes[0]

print("----------------------------------------")
print(f"input:{0} output:{select_joke(0)}")
print(f"input:{None} output:{select_joke(None)}")
print(f"input:{''} output:{select_joke('')}")
print("----------------------------------------")

Output:

----------------------------------------
input:0 output:This is default joke
input:None output:This is default joke
input: output:This is default joke
----------------------------------------