_get_sequence

        Low-level api: Return a list of children of a parent with the same tag
        within the scope.

        Parameters
        ----------

        scope : `list`
            List members can be an element, or a tuple of two elements.

        tag : `str`
            Identifier in `{url}tagname` notation.

        parent : `Element`
            The parent node.

        Returns
        -------

        list
            A list of children with the same tag within the scope.

def _get_sequence(scope, tag, parent):
        '''_get_sequence

        Low-level api: Return a list of children of a parent with the same tag
        within the scope.

        Parameters
        ----------

        scope : `list`
            List members can be an element, or a tuple of two elements.

        tag : `str`
            Identifier in `{url}tagname` notation.

        parent : `Element`
            The parent node.

        Returns
        -------

        list
            A list of children with the same tag within the scope.
        '''

        new_scope = []
        for item in scope:
            if isinstance(item, tuple):
                one, two = item
                if one.getparent() == parent:
                    new_scope.append(one)
                else:
                    new_scope.append(two)
            else:
                new_scope.append(item)
        return [child for child in parent.iterchildren(tag=tag)
                if child in new_scope]