Devise Strong Parameters Problem

[bonekost]

Hey,

I got small problem with setting up strong parameters.
I try to use this method:

def configure_permitted_parameters 
  devise_parameter_sanitizer.for(:sign_in) { |u| u.permit(:username, :email) } 
end

but it throws error.

#<Proc:0x007fd4da526578@app/controllers/application_controller.rb

When I try to use single method for add single parameter it works perfectly

def configure_permitted_parameters 
  devise_parameter_sanitizer.for(:sign_up) << :username 
end

Thanks

Ruby 2.2.2
Rails 4.2.3
Devise 3.5.1