Problem
The python "try" keyword is very powerful in that it can, among other things, prevent a program from ending abnormally because of invalid numeric input.
Write python program with two functions/modules that does the following:
1) main() accepts input and calls a function to test if the input is a number and displays a message regarding the result of that numeric test
2) numTest() is passed an input string, tests to see if the string is numeric and returns the necessary information to main()
3) a NULL input (just pressing the enter key) ends the program
4) Do not use the builtin python function for numeric testing