code: def find_keys(args):
      
      key = args['--key']
      if key:
          return [key]
  
      keyfile = args['--apikeys']
      if keyfile:
          return read_keyfile(keyfile)
  
      envkey = os.environ.get('TINYPNG_API_KEY', None)
      if envkey:
          return [envkey]
  
      local_keys = join(abspath("."), "tinypng.keys")
  
      if isfile(local_keys):
          return read_keyfile(local_keys)
  
      home_keys = join(expanduser("~/.tinypng.keys"))
      if isfile(home_keys):
          return read_keyfile(home_keys)
  
      return []
docs: Get keys specified in arguments
  
      returns list of keys or None