def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def draw(self, context):
        layout = self.layout

        layout.operator(
                "wm.url_open", text="Add-ons Catalog", icon='URL',
                ).url = "http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts"

        layout.separator()

        layout.operator(
                "wm.url_open", text="How to share your add-on", icon='URL',
                ).url = "http://wiki.blender.org/index.php/Dev:Py/Sharing"
        layout.operator(
                "wm.url_open", text="Add-on Guidelines", icon='URL',
                ).url = "http://wiki.blender.org/index.php/Dev:2.5/Py/Scripts/Guidelines/Addons"
        layout.operator(
                "wm.url_open", text="API Concepts", icon='URL',
                ).url = bpy.types.WM_OT_doc_view._prefix + "/info_quickstart.html"
        layout.operator("wm.url_open", text="Add-on Tutorial", icon='URL',
                ).url = "http://www.blender.org/api/blender_python_api_current/info_tutorial_addon.html"