Event_calendat error wrong number of arguments (1 for 2)

[Moises Zaragoza]

I was able to track down this error to the app/helpers/calendar_helper.rb

def event_calendar_options
    {-
      :year => @year,
      :month => @month,
      :event_strips => @event_strips,
      :month_name_text => I18n.localize(@shown_month, :format => "%B %Y"),
      :previous_month_text => "<< " + month_link(@shown_month.prev_month),
      :next_month_text => month_link(@shown_month.next_month) + " >>"
    }
  end

to the line
:previous_month_text => "<< " + month_link(@shown_month.prev_month),
      :next_month_text => month_link(@shown_month.next_month) + " >>"

when I add a debuger and i run month_link(@shown_month.prev_month) it tells  me wrong number of arguments (1 for 2)

what can i do or where should i search