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: row_extensions.rb
    path of file: ./repos/mushroom-observer/app/classes/report
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Report
  module RowExtensions
    def year
      @dat
    
    def best_long(prec = 4)
      long = obs_long(prec)
      return long if long.present?

      east = loc_east(prec + 10)
      west = loc_west(prec + 10)
      return nil unless east && west

      ((east + west) / 2).round(prec)
    end