Handle siret with whitespaces

app/models/siret.rb

@@ -1,7 +1,15 @@
 class Siret
   include ActiveModel::Model
+  include ActiveModel::Validations::Callbacks
+
   attr_accessor :siret
 
   validates_presence_of :siret
   validates :siret, siret_format: true
+
+  before_validation :remove_whitespace
+
+  def remove_whitespace
+    siret.delete!(' ')
+  end
 end