docs: def get_form_context(self, obj, ns=None):
          """Return a dict: form instance, action button, submit url...
  
          Used by macro m_tags_form(entity)
          """
          return {
              "url": url_for("entity_tags.edit", object_id=obj.id),
              "form": self.entity_tags_form(obj)(obj=obj, ns=ns),
              "buttons": [EDIT_BUTTON],
          }