code: def render_latex_text(input_text, nest_in_doc=False, preamb_extra=None,
                        appname='utool', verbose=None):
      
      import utool as ut
      if verbose is None:
          verbose = ut.VERBOSE
      dpath = ut.ensure_app_resource_dir(appname, 'latex_tmp')
      # put a latex framgent in a full document
      # print(input_text)
      fname = 'temp_render_latex'
      pdf_fpath = ut.compile_latex_text(
          input_text, dpath=dpath, fname=fname, preamb_extra=preamb_extra,
          verbose=verbose)
      ut.startfile(pdf_fpath)
      return pdf_fpath
docs: compiles latex and shows the result