Write a function named create$\_$mat that creates a square matrix of an arbitrary size having the structure given in the example below. This function should take the size of a square matrix as an integer $($n$)$ and outputs the special matrix $($S$)$ as shown in the example below. You MUST use numpy arrays to create this matrix.

The code has already been provided to define a function named create$\_$mat that accepts the input variable n and returns the output variable S$.$

Examples:

Note that n is defined as input to the function. Do not overwrite values in this variable in your code. Be sure to assign a value to the function output variable $($S$).$