Pair Programming Stack Implementation

Create a stack with methods to add, remove, and find elements.

Implement a Stack class and a helper function that processes operations. add(value) pushes a value, remove() returns and removes the top value, and returns None when empty, while find(value) returns whether the value exists. The stack must preserve LIFO order and allow duplicate values.

Input and Output

process_stack_operations(operations) receives a list of operation arrays. Each operation is ["add", value], ["remove"], or ["find", value]. Return one result per operation: None for add, the removed value for remove, and a Boolean for find.