Allow empty label and help text

django_forms_as_jsonschema/jsonschema.py

@@ -69,8 +69,8 @@ class JSONSchema:
     def add_field(self, name, field):
         new_field = {
             "type": "string",
-            "title": str(field.label),
-            "description": str(field.help_text),
+            "title": str(field.label or ""),
+            "description": str(field.help_text or ""),
             "readOnly": field.disabled
         }