docs: def directory():
      """Construct hitman_dir from os name"""
      home = os.path.expanduser('~')
      if platform.system() == 'Linux':
          hitman_dir = os.path.join(home, '.hitman')
      elif platform.system() == 'Darwin':
          hitman_dir = os.path.join(home, 'Library', 'Application Support',
                                    'hitman')
      elif platform.system() == 'Windows':
          hitman_dir = os.path.join(os.environ['appdata'], 'hitman')
      else:
          hitman_dir = os.path.join(home, '.hitman')
      if not os.path.isdir(hitman_dir):
          os.mkdir(hitman_dir)
      return hitman_dir