docs: def ExistsWithType(self,
                       urn,
                       aff4_type=None,
                       follow_symlinks=True,
                       age=NEWEST_TIME,
                       token=None):
      """Checks if an object with a given URN and type exists in the datastore.
  
      Args:
        urn: The urn to check.
        aff4_type: Expected object type.
        follow_symlinks: If object opened is a symlink, follow it.
        age: The age policy used to check this object. Should be either
          NEWEST_TIME or a time range given as a tuple (start, end) in
          microseconds since Jan 1st, 1970.
        token: The Security Token to use for opening this item.
  
      Raises:
        ValueError: if aff4_type is not specified.
  
      Returns:
        True if there's an object with a matching type at a given URN, False
        otherwise.
      """
      if not aff4_type:
        raise ValueError("aff4_type can't be None")
  
      try:
        self.Open(
            urn,
            aff4_type=aff4_type,
            follow_symlinks=follow_symlinks,
            age=age,
            token=token)
        return True
      except InstantiationError:
        return False