'Create an instance of theme.'

def create(self, name):

    if (name not in self.themes):
        self.load_extra_theme(name)
    if (name not in self.themes):
        if (name == 'sphinx_rtd_theme'):
            raise ThemeError(__('sphinx_rtd_theme    is    no    longer    a    hard    dependency    since    version    1.4.0.    Please    install    it    manually.(pip    install    sphinx_rtd_theme)'))
        else:
            raise ThemeError((__('no    theme    named    %r    found    (missing    theme.conf?)') % name))
    return Theme(name, self.themes[name], factory=self)
