def METHOD_NAME(usernames_file):
  """Creates inputs for prediction given is file with usernames.
  Args:
    usernames_file: path to a file containing usernames of users to get
      recommendations for.
  Returns:
    A list of input dicts to be passed to the model for prediction.
  """
  with open(usernames_file, "r") as f:
    lines = f.read().splitlines()
  instances = []
  for line in lines:
    instance = {
        constants.USER_KEY: "",
        constants.ITEM_KEY: "",
    }
    instance.update(json.loads(line))
    instances.append(instance)
  return instances