input: Write a function to remove all whitespaces from each string in a given list of strings. If the input list is empty, return an empty list.
  assert remove_whitespace(['Hello  World', 'Hi  there', 'Good  Morning']) == ['HelloWorld', 'Hithere', 'GoodMorning']
  assert remove_whitespace([]) == []
output: def remove_whitespace(strings):
      return [''.join(s.split()) for s in strings]