Return all the Roles under the Identity namespace.

        Returns:
            (list): A list containing all the Roles under the Identity
                namespace.

def get_roles(self):
        """Return all the Roles under the Identity namespace.

        Returns:
            (list): A list containing all the Roles under the Identity
                namespace.
        """

        prefix = _IDENTITY_NS + _ROLE_NS
        rolelist_list = [
            _create_from_bytes(d, identity_pb2.RoleList)
            for _, d in self._state_view.leaves(prefix=prefix)
        ]
        roles = []
        for role_list in rolelist_list:
            for role in role_list.roles:
                roles.append(role)
        return sorted(roles, key=lambda r: r.name)