In Python, "monkey patching" refers to the dynamic modification of a class or module at runtime. This is often done to add or modify the behavior of a module or class without modifying the source code of the module or class directly.

Here is an example of how monkey patching can be used in Python:


# Define a simple class with a method that returns a string
class MyClass:
    def greet(self):
        return "Hello, world!"

# Create an instance of the class
obj = MyClass()

# Print the original greeting
print(obj.greet())  # Output: "Hello, world!"

# Monkey patch the greet method to return a different string
def new_greet(self):
    return "Goodbye, world!"

MyClass.greet = new_greet

# Print the modified greeting
print(obj.greet())  # Output: "Goodbye, world!"

In this example, we define a class MyClass with a method greet that returns a string. We then create an instance of the class and print the original greeting. Next, we define a new function new_greet that returns a different string. Finally, we use monkey patching to replace the original greet method with the new new_greet function. When we print the modified greeting, we see that it has been changed to the string returned by the new_greet function.

It's important to note that monkey patching can have unintended consequences and should be used with caution. In general, it's better to modify the source code of a class or module directly if possible. Monkey patching is most useful in cases where you don't have access to the source code, or where you need to make a quick, temporary change to the behavior of a class or module.