old_contents: import subprocess
  from thefuck.utils import for_app, replace_command, eager
  
  
  @for_app('ifconfig')
  def match(command):
      return 'error fetching interface information: Device not found' \
             in command.stderr
  
  
  @eager
  def _get_possible_interfaces():
      proc = subprocess.Popen(['ifconfig', '-a'], stdout=subprocess.PIPE)
      for line in proc.stdout.readlines():
          line = line.decode()
          if line and line != '\n' and not line.startswith(' '):
              yield line.split(' ')[0]
  
  
  def get_new_command(command):
      interface = command.stderr.split(' ')[0][:-1]
      possible_interfaces = _get_possible_interfaces()
      return replace_command(command, interface, possible_interfaces)
  
  
  
new_contents: import subprocess
  from thefuck.utils import for_app, replace_command, eager
  
  
  @for_app('ifconfig')
  def match(command):
      return 'error fetching interface information: Device not found' \
             in command.stderr
  
  
  @eager
  def _get_possible_interfaces():
      proc = subprocess.Popen(['ifconfig', '-a'], stdout=subprocess.PIPE)
      for line in proc.stdout.readlines():
          line = line.decode()
          if line and line != '\n' and not line.startswith(' '):
              yield line.split(' ')[0]
  
  
  def get_new_command(command):
      interface = command.stderr.split(' ')[0][:-1]
      possible_interfaces = _get_possible_interfaces()
      return replace_command(command, interface, possible_interfaces)
  
subject: Fix flake8 errors: W391 blank line at end of file