Dots and dashes

There are split and join string methods as well (see Week 3!). Write a function called chain_words(str) which takes in one parameter which is a string that holds multiple words separated by spaces. Your function should return a string with the words chained together with an - (hyphen). You can first split the words at spaces and then join the words with - (hyphen). You can achieve this by using split and join methods respectively.

Sample Input 1:

hello world

Sample Output 1:

hello-world

Sample Input 2:

Connect the words in this sentence

Sample Output 2:

Connect-the-words-in-this-sentence