Write a function named "locate" that gets an array and value and returns true if specified value exist in a multidimentional array.
Example:
locate(['a','b',['c','d',['e']]],'e'); // should return true
locate(['a','b',['c','d',['e']]],'a'); // should return true
locate(['a','b',['c','d',['e']]],'f'); // should return false