Accidentally Overwriting Built-In Functions: A Restoration Guide

Overwriting built-in functions by accident can be frustrating, especially when you're working with a long-running session. Fortunately, there are ways to restore the original functionality without resorting to restarting your session.

Solution: Deleting the Masking Variable

To restore the original built-in function, simply delete the variable name that you used to overwrite it. For example, if you accidentally set set as a variable, run the following command:

del set

Now, set will refer to the original built-in set function.

Alternative: Accessing Built-Ins Through the Builtins Module

If you want to use the original built-in function from your overwritten function, you can access it through the builtins module. In Python 3, this module is called builtins, while in Python 2, it's called __builtin__. For example, if you overwrote set but want to use the original one, you can do:

import builtins
original_set = builtins.set

Determining the Masking Namespace

If you're unsure where the masking name is defined, check the namespaces from your current one up to the built-ins. Use the scoping rules described in "Short description of the scoping rules?" to determine which scopes may be relevant.