@abc.abstractmethod<EOL><INDENT>def alias_package(self, package_id, alias_id):<DEDENT>
pass<EOL>
Adds an ``Id`` to a ``Package`` for the purpose of creating compatibility.

        The primary ``Id`` of the ``Package`` is determined by the
        provider. The new ``Id`` performs as an alias to the primary
        ``Id``. If the alias is a pointer to another package it is
        reassigned to the given package ``Id``.

        :param package_id: the ``Id`` of a ``Package``
        :type package_id: ``osid.id.Id``
        :param alias_id: the alias ``Id``
        :type alias_id: ``osid.id.Id``
        :raise: ``AlreadyExists`` -- ``alias_id`` is already assigned
        :raise: ``NotFound`` -- ``package_id`` not found
        :raise: ``NullArgument`` -- ``package_id`` or ``alias_id`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

        *compliance: mandatory -- This method must be implemented.*