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: datetime.rb
    path of file: ./repos/openproject/lib_static/plugins/acts_as_journalized/lib/journal_formatter
    
    the code of the file until where you have to start completion: #-- copyright
# OpenProject is an open source project 
    
    def format_values(values)
      values.map do |v|
        if v.nil?
          nil
        else
          format_date(v.to_date)
        end
      end