old_contents: from six.moves import filterfalse
  from thefuck.utils import replace_argument
  from thefuck.specific.git import git_support
  
  
  @git_support
  def match(command):
      args = command.script_parts[2:]
      files = list(filterfalse(is_option, args))
      return ('diff' in command.script and
              '--no-index' not in command.script and
              len(command.stdout) is 0 and
              len(files) is 2)
  
  def is_option(script_part):
      return script_part.startswith('-')
  
  @git_support
  def get_new_command(command):
      return replace_argument(command.script, 'diff', 'diff --no-index')
  
new_contents: from thefuck.utils import replace_argument
  from thefuck.specific.git import git_support
  
  
  @git_support
  def match(command):
      files = [arg for arg in command.script_parts[2:]
               if not arg.startswith('-')]
      return ('diff' in command.script
              and '--no-index' not in command.script
              and not command.stdout
              and len(files) == 2)
  
  
  @git_support
  def get_new_command(command):
      return replace_argument(command.script, 'diff', 'diff --no-index')
  
subject: Fix code style