Question Two.

Background

Filtering data is a common task in programming, allowing you to remove unwanted elements based on specific criteria. Python's built$-$in filter$()$ function is a powerful tool for this purpose. However, implementing a custom filter function can provide deeper insights into iterative processing and conditional logic.

Task

Write a Python program that defines a function named custom$\_$filter to filter elements from a list. The function should mimic the behavior of Python's built$-$in filter$()$ but will be implemented manually to understand the underlying mechanism.