diff --git a/form_designer/models.py b/form_designer/models.py
index 79ace53..ae6e7a9 100644
--- a/form_designer/models.py
+++ b/form_designer/models.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 import warnings
 from functools import partial
 
@@ -51,7 +53,7 @@ def validate_comma_separated_emails(value):
     for v in value.split(","):
         validate_email(v.strip())
 
-def email_field_choices(form: forms.ModelForm | None, required: bool=True) -> list[tuple[str, str]]:
+def email_field_choices(form: Optional[forms.ModelForm], required: bool=True) -> list[tuple[str, str]]:
     if not form or not form.instance or not form.instance.pk:
         return []
     email_fields = form.instance.fields.filter(type='email')