code: def find_unique_identity(session, uuid):
      
      uidentity = session.query(UniqueIdentity). \
          filter(UniqueIdentity.uuid == uuid).first()
  
      return uidentity
docs: Find a unique identity.
  
      Find a unique identity by its UUID using the given `session`.
      When the unique identity does not exist the function will
      return `None`.
  
      :param session: database session
      :param uuid: id of the unique identity to find
  
      :returns: a unique identity object; `None` when the unique
          identity does not exist