Editing Duck typing (section)

==Examples==
This simple example in [[Python (programming language)|Python]] 3 demonstrates how any object may be used in any context until it is used in a way that it does not support.

<syntaxhighlight lang="python" line="1">
class Duck:
    def swim(self):
        print("Duck swimming")

    def fly(self):
        print("Duck flying")

class Whale:
    def swim(self):
        print("Whale swimming")

for animal in [Duck(), Whale()]:
    animal.swim()
    animal.fly()
</syntaxhighlight>

Output:
<syntaxhighlight lang="output">
Duck swimming
Duck flying
Whale swimming
AttributeError: 'Whale' object has no attribute 'fly'
</syntaxhighlight>
If it can be assumed that anything that can swim is a duck because ducks can swim, a whale could be considered a duck; however, if it is also assumed that a duck must be capable of flying, the whale will not be considered a duck.