Retrieve a value set for a subject's attribute.

    This method is easy to use but always gets the latest version of the
    attribute. It is more flexible and efficient to use the other Resolve
    methods.

    Args:
      subject: The subject URN.
      attribute: The attribute.

    Returns:
      A (value, timestamp in microseconds) stored in the datastore cell, or
      (None, 0). Value will be the same type as originally stored with Set().

    Raises:
      AccessError: if anything goes wrong.

def Resolve(self, subject, attribute):
    """Retrieve a value set for a subject's attribute.

    This method is easy to use but always gets the latest version of the
    attribute. It is more flexible and efficient to use the other Resolve
    methods.

    Args:
      subject: The subject URN.
      attribute: The attribute.

    Returns:
      A (value, timestamp in microseconds) stored in the datastore cell, or
      (None, 0). Value will be the same type as originally stored with Set().

    Raises:
      AccessError: if anything goes wrong.
    """
    for _, value, timestamp in self.ResolveMulti(
        subject, [attribute], timestamp=self.NEWEST_TIMESTAMP):

      # Just return the first one.
      return value, timestamp

    return (None, 0)