You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: filterable.rb
    path of file: ./repos/maybe/app/controllers/concerns
    
    the code of the file until where you have to start completion: module Filterable
   
    
      def set_period
        @period = Period.find_by_name(params[:period])
        if @period.nil?
          start_date = params[:start_date].presence&.to_date
          end_date = params[:end_date].presence&.to_date
          if start_date.is_a?(Date) && end_date.is_a?(Date) && start_date <= end_date
            @period = Period.new(name: "custom", date_range: start_date..end_date)
          else
            params[:period] = "last_30_days"
            @period = Period.find_by_name(params[:period])
          end