Write $($define$)$ a function named count$\_$vowels, that takes one argument $($you can safely assume that arguments will always be a strwith a length of at least one$).$ When this function is called, it should return an int that indicates the total number of vowels $($a$,$ e$,$ i$,$ o$,$ u$)$ in the argument.

Examples:

count$\_$vowels$(\text{'}$hello$!\text{'})$ will return $2$

count$\_$vowels$(\text{'}$bcdfgh$\text{'})$ will return $0$

count$\_$vowels$(\text{'}$aeiou$\text{'})$ will return $5$

You may wish to write some additional code to test your function. Please be sure that you delete $($or comment out$)$ any test code before you submit your solution. The only code in your solution when you submit should be the required function definition.