Basic scaling
Input
list(CustomContainer([1, 2, 3], 2))
Output
[2, 4, 6]
Each element 1,2,3 is multiplied by multiplier 2 producing 2,4,6.
Full lesson preview
Implement __iter__ for a Custom Container
Implement iteration for a container so instances can be iterated over, multiplied by a per-container multiplier.
Python practice25 minMagic Methods & Operator OverloadingAdvancedLast updated April 11, 2026
Problem statement
You are given a CustomContainer class that stores an ordered collection of items and a multiplier. Implement the __iter__ magic method so that iterating over an instance yields each stored item multiplied by the container's multiplier (in the original order). The iterator should work with built-in functions like list(), sum(), and for-loops. Do not modify other methods or attributes.
Task
Write the __iter__ dunder method to allow iteration over stored items with each item scaled by the container's multiplier.
Examples
Input format
Calls will construct CustomContainer(items, multiplier) and then iterate over it (e.g. list(container) or sum(container)).
Output format
An iterable sequence of items resulting from item * multiplier, returned as whatever expression demands (list, sum, etc.).
Constraints
Do not change the class signature. Implement only __iter__. The items can be any numeric types; multiplier may be any numeric type as well. Maintain original order.
Samples
Sample 1
Input
list(CustomContainer([0, 5, -2], 3))
Output
[0, 15, -6]
0*3=0, 5*3=15, -2*3=-6