Exes and Ohs

Ruby

Check to see if a string has the same amount of 'x's and 'o's. The method must return a boolean and be case insensitive. The string can contain any char.

Examples input/output:

xo("ooxx") => true
xo("xooxx") => false
xo("ooxXm") => true
xo("zpzpzpp") => true // when no 'x' and 'o' is present should return true
xo("zzoo") => false

Create a method called xo(str) that accepts 1 parameter.