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 _init_renderers(self):
        """Initializes the cell renderers"""
        # We hide the columns headers
        self.set_headers_visible(False)
        # For the backend icon
        pixbuf_cell = Gtk.CellRendererPixbuf()
        tvcolumn_pixbuf = Gtk.TreeViewColumn('Icon', pixbuf_cell)
        tvcolumn_pixbuf.add_attribute(pixbuf_cell, 'pixbuf', self.COLUMN_ICON)
        self.append_column(tvcolumn_pixbuf)
        # For the backend name
        text_cell = Gtk.CellRendererText()
        tvcolumn_text = Gtk.TreeViewColumn('Name', text_cell)
        tvcolumn_text.add_attribute(text_cell, 'markup', self.COLUMN_TEXT)
        self.append_column(tvcolumn_text)
        text_cell.connect('edited', self.cell_edited_callback)
        text_cell.set_property('editable', True)
        # For the backend tags
        tags_cell = Gtk.CellRendererText()
        tvcolumn_tags = Gtk.TreeViewColumn('Tags', tags_cell)
        tvcolumn_tags.add_attribute(tags_cell, 'markup', self.COLUMN_TAGS)
        self.append_column(tvcolumn_tags)