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: postgresql.rb
    path of file: ./repos/reports_kit/lib/reports_kit/reports/adapters
    
    the code of the file until where you have to start completion: module ReportsKit
  module Reports
    module Adapters
      class Postgresql
        def self.truncate_to_day(column)
    
    
        def self.truncate_to_week(column)
          case ReportsKit.configuration.first_day_of_week
          when :sunday
            "DATE_TRUNC('week', #{column}::timestamp + '1 day'::interval) - '1 day'::interval"
          when :monday
            "DATE_TRUNC('week', #{column}::timestamp)"
          else
            raise ArgumentError.new("Unsupported first_day_of_week: #{ReportsKit.configuration.first_day_of_week}")
          end