Localization expected, got HashWithIndifferentAccess

Well I Have this models

Localization
has_many :event

Event
belongs_to :localization

in the view events/new.html.erb

  <% f.fields_for :localization do |L| %>

    <%= l.text_field :country %>
    <%= l.text_field :state %>
    <%= l.text_field :city %>

  <% end %>

the events controller is ust saving the event model.

But when I submit the page I get "Localization expected, got
HashWithIndifferentAccess" I tried to modify the controller in many
ways, but this apper to be happening before arrive in the controller.

By the way, I will use this space also to ask you if there is a better
way to associate an event with an location making easy to reuse the
same location for different events and other models I will have?

Thank you

Anybody have an update to this question?

Try to specify in your Event model:
  accepts_nested_attributes_for :localization

It should work, but typically it's used from parent to child (when
event subform is inside location form).

Also has_many :event doesn't have much sence -- either has_one either
eventS.

Dmitry