def install_pip(self, package, save=True, save_dev=False):
        """Installs a pip package.

        :param save: if `True`, pins the package to the Hydrogen requirements
            YAML file.
        :param save_dev: if `True`, pins the package as a development
            dependency to the Hydrogen requirements YAML file.
        :param return: a **single** :class:`Requirement` object, representing
            the installed version of the given package.
        """
        requirement = Requirement.coerce(package)
        click.echo("pip install " + requirement.package)
        cmd = envoy.run("pip install {}".format(str(requirement)))
        if cmd.status_code == 0:
            installed_packages = get_installed_pypackages()
            package = installed_packages[requirement.package]
            requirement.version = "=={}".format(package.version)
            if save:
                self.requirements["all"].add(requirement)
            if save_dev:
                self.requirements["dev"].add(requirement)
            if save or save_dev:
                self.requirements.save()
            return requirement
        else:
            fatal(cmd.std_err)
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"