input: Write a python function that utilizes regex to eliminate all spaces from the input string.
  assert remove_spaces(' Google    Flutter ') == 'GoogleFlutter'
  assert remove_spaces(' Google    Dart ') == 'GoogleDart'
  assert remove_spaces(' iOS    Swift ') == 'iOSSwift'
output: def remove_spaces(input_string):
      import re
      return re.sub(r'\s+', '', input_string)