diff --git a/lib/active_form/form_collection.rb b/lib/active_form/form_collection.rb
index fe2f5cc..65cf92e 100644
--- a/lib/active_form/form_collection.rb
+++ b/lib/active_form/form_collection.rb
@@ -134,11 +134,11 @@ def aggregate_form_errors
 
     def fetch_models
       associated_records = parent.send(association_name)
-      
+
       associated_records.each do |model|
         form = Form.new(association_name, parent, proc, model)
         forms << form
-        form.instance_eval &proc
+        form.instance_eval(&proc) if proc.present?
       end
     end
 
@@ -146,7 +146,7 @@ def initialize_models
       records.times do
         form = Form.new(association_name, parent, proc)
         forms << form
-        form.instance_eval &proc
+        form.instance_eval(&proc) if proc.present?
       end
     end
 
@@ -178,4 +178,4 @@ def create_form
     end
   end
 
-end
\ No newline at end of file
+end