Let’s say we have our dictionary of building heights from the last exercise:

building_heights = {"Burj Khalifa": 828, "Shanghai Tower": 632, "Abraj Al Bait": 601, "Ping An": 599, "Lotte World Tower": 554.5, "One World Trade": 541.3}

What if we wanted to know the height of the Landmark 81 in Ho Chi Minh City? We could try:

print(building_heights["Landmark 81"])

But "Landmark 81" does not exist as a key in the building_heights dictionary! So this will throw a KeyError:

KeyError: 'Landmark 81'

One way to avoid this error is to first check if the key exists in the dictionary:

key_to_check = "Landmark 81"

if key_to_check in building_heights:
  print(building_heights["Landmark 81"])

This will not throw an error, because key_to_check in building_heights will return False, and so we never try to access the key.