old_contents: # mypy: ignore-errors
  
  import os
  
  
  def print_warning(*lines):
      print('**************************************************')
      for line in lines:
          print('*** WARNING: %s' % line)
      print('**************************************************')
  
  
  def get_path(key):
      return os.environ.get(key, '').split(os.pathsep)
  
  
  def search_on_path(filenames):
      for p in get_path('PATH'):
          for filename in filenames:
              full = os.path.join(p, filename)
              if os.path.exists(full):
                  return os.path.abspath(full)
      return None
  
new_contents: import os
  from typing import List, Optional
  
  
  def print_warning(*lines: str) -> None:
      print('**************************************************')
      for line in lines:
          print('*** WARNING: %s' % line)
      print('**************************************************')
  
  
  def get_path(key: str) -> List[str]:
      return os.environ.get(key, '').split(os.pathsep)
  
  
  def search_on_path(filenames: List[str]) -> Optional[str]:
      for p in get_path('PATH'):
          for filename in filenames:
              full = os.path.join(p, filename)
              if os.path.exists(full):
                  return os.path.abspath(full)
      return None
  
subject: add type to install_utils