rated list of
          :class:`Deb822`,
          their components form a disjunction, i.e. they have to be OR-ed
          together
        - member of the inner lists are dictionaries with the following keys:

          ``name``
            package (or virtual package) name
          ``version``
            A pair <`operator`, `version`> if the relationship is
            versioned, None otherwise. operator is one of ``<<``,
            ``<=``, ``=``, ``>=``, ``>>``; version is the given version as
            a string.
          ``arch``
            A list of pairs <`enabled`, `arch`> if the
            relationship is architecture specific, None otherwise.
            Enabled is a boolean (``False`` if the architecture is
            negated with ``!``, ``True`` otherwise), arch the
            Debian architecture name as a string.
          ``restrictions``
            A list of lists of tuples <`enabled`, `profile`>
            if there is a restriction formula defined, ``None``
            otherwise. Each list of tuples represents a restriction
            list while each tuple represents an individual term
            within the restriction list. Enabled is a boolean
            (``False`` if the restriction is negated with ``!``,
            ``True`` otherwise). The profile is the name of the
            build restriction.
            https://wiki.debian.org/BuildProfileSpec

          The arch and restrictions tuples are available as named tuples so
          elements are available as `term[0]` or alternatively as
          `term.enabled` (and so forth).

        Examples:

        ``"emacs | emacsen, make, debianutils (>= 1.7)"``
        becomes::

          [
            [ {'name': 'emacs'}, {'name': 'emacsen'} ],
            [ {'name': 'make'} ],
            [ {'name': 'debianutils', 'version': ('>=', '1.7')} ]
          ]

        ``"tcl8.4-dev, procps [!hurd-i386]"``
        becomes::

          [
            [ {'name': 'tcl8.4-dev'} ],
            [ {'name': 'procps', 'arch': (false, 'hurd-i386')} ]
          ]

        ``"texlive <!cross>"``
        becomes::

          [
            [ {'name': 'texlive', 'restriction': [[(false, 'cross')]]} ]
          ]
        c