Write a function and provide a program to test it$.$ The program should be called 'smallest', it should have three arguments, and it should return the smallest of those three numbers. Be sure to follow the format described in the Canvas instructions for this assignment. The program should ask the user for the three numbers $($floating point numbers$),$ use the function to find the smallest, and then print that returned value.

def smallest$($x$,$ y$,$ z$)($returning the smallest of the arguments$)$

The input and out should look like this $($the user entered numbers are in bold for example only$)$:

Enter number $1$: $20$

Enter number $2$: $15$

Enter number $3$: $45$

The smallest is: $15\mathrm{.}0$