Exercise (b): Write a program to perform a linear search to find the positions (indices) pf all instances of "cup" (irrespective of the case) in the following list. Note: you are not allowed to use the index() function.
If the given list is ["cup", 20, 2.3, "football", True, "Cup", 56, 34, "CuP", 3]
The output must be [0, 5, 8].