code: def parse_form(self, req, name, field):
          
          form = self._cache.get("form")
          if form is None:
              self._cache["form"] = form = parse_form_body(req)
          return core.get_value(form, name, field)
docs: Pull a form value from the request.
  
          .. note::
  
              The request stream will be read and left at EOF.