Write a Python program to: Read the amount of a purchase from the user Calculate the amount of GST Calculate the total with GST Print out a formatted sales receipt (example below) Your program should include a main function and at least one other function. Use appropriate Python style convention. Assume that the GST is 5% and that the user provides valid input. The output should look like the following (where 10.50 is an example input, this value should not be hard coded): Enter the amount of your purchase: 10.50 Amount of purchase: $10.50 Amount of GST: $0.53 Total purchase: $11.03