//Character classes are one of the primary means of “grouping” characters
//in a regex pattern without necessarily enforcing an order to those characters.
[abc] Includes any of the contained characters
[^abc] Excludes all of the contained characters
[a-z] Includes any of the contained characters across a range
. Any character except newline
w Any word character (alphanumeric and underscore)
d Any digit [0-9]
s Whitespace (spaces, tabs, line breaks)