code: def get_catalog(self):
          
  
          catalog_data = fixture_bucket.get(self.input['form']['catalog'])
  
          # define add or edit based on catalog data exists
          add_or_edit = "Edit" if catalog_data.exists else "Add"
  
          # generate form
          catalog_edit_form = CatalogEditForm(
              current=self.current,
              title='%s: %s' % (add_or_edit, self.input['form']['catalog']))
  
          # add model data to form
          if catalog_data.exists:
              if type(catalog_data.data) == list:
                  # if catalog data is an array it means no other language of value defined, therefor the value is turkish
                  for key, data in enumerate(catalog_data.data):
                      catalog_edit_form.CatalogDatas(catalog_key=key or "0", en='', tr=data)
              if type(catalog_data.data) == dict:
                  for key, data in catalog_data.data.items():
                      catalog_edit_form.CatalogDatas(catalog_key=key, en=data['en'], tr=data['tr'])
  
          else:
              catalog_edit_form.CatalogDatas(catalog_key="0", en='', tr='')
  
          self.form_out(catalog_edit_form)
  
          # schema key for get back what key will be saved, used in save_catalog form
          self.output["object_key"] = self.input['form']['catalog']
docs: Get existing catalog and fill the form with the model data.
          If given key not found as catalog, it generates an empty catalog data form.