-- | Write a function, called greet, that takes a string representing a

-- | persons name and says "Hi " to that person.

-- | There has to be only a single space between Hi and the person's name in the result string.

-- | There should not be any other spaces in the result string.

-- | There should not be any punctuation marks or any additional characters.

-- | If the name provided is empty, your function should return "Hi there".

-- -- >>> greet "Ann" -- "Hi Ann"

-- >>> greet "Peter" -- "Hi Peter"

-- >>> greet "" -- "Hi there"