def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def draw(self, context):
        layout = self.layout

        split = layout.split()
        row = split.row()
        row.label("")
        row = split.row()
        row.label("Interaction:")

        text = bpy.path.display_name(context.window_manager.keyconfigs.active.name)
        if not text:
            text = "Blender (default)"
        row.menu("USERPREF_MT_appconfigs", text=text)