Create a program named Lab11a_Act1.py that utilizes the shoelace formula via the following steps:
1. Create a function named readfile that takes in as an argument a filename and returns a list of points of arbitrary length. A sample input file is provided with this lab. Each element in the list of points should itself be a list of one point. For the sample input file given, your function should return [[3, 4], [5, 6], [9, 5], [12, 8], [5, 11]].
2. Create a function named cross that takes in two arguments, both of which are a list of one point, and returns the cross-product. This one step of the shoelace method. For example, if the points [1, 2] and [3, 4] are passed to the function, it will return -2. Cross product: (1 * 4) - (2 * 3) = -2
3. Create a function named shoelace that takes in as an argument a list of points and returns the area of the polygon calculated via the shoelace formula. The list of points passed to the function is the same list returned by your readfile function. Your shoelace function should call your cross function.
4. Create a function named main that does not take in any arguments nor return any values. This function should take as input from the user a filename, and print the area of the polygon. Your main function should call your readfile and shoelace functions. Format our output as shown below.
5. Finally, in your main code type the following:
if main ': name main() You should NOT include any other executable lines in your main code. Example output (using input Lablla_input. txt): Please enter the filename: Lab11a_input.txt The area of the polygon is 30.0 X,Y 3,4 5,6 9,5 12,8 5,11
