Correct logic if not check_unique_element_id
@@ -80,7 +80,7 @@ class SectionMixin(object):
# when adding a new element, `element_id` can not be validated for uniqueness
postfix = 0
# check if form simplewarpper has function check_unique_element_id
- if 'check_unique_element_id' in dir(form):
+ if not 'check_unique_element_id' in dir(form):
form_ = SectionForm
else:
form_ = form
