code: def _init_metadata(self):
          
          super(PDFPreviewFormRecord, self)._init_metadata()
          self._preview_metadata = {
              'element_id': Id(self.my_osid_object_form._authority,
                               self.my_osid_object_form._namespace,
                               'file'),
              'element_label': 'File',
              'instructions': 'accepts an Asset Id',
              'required': True,
              'read_only': False,
              'linked': False,
              'array': False,
              'default_id_values': [''],
              'syntax': 'ID',
              'id_set': []
          }
docs: stub