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: response.rb
    path of file: ./repos/metasploit-framework/lib/rex/proto/sip
    
    the code of the file until where you have to start completion: # encoding: binary

module Rex
  module Pr
    
        def self.extract_headers(message)
          pairs = message.scan(/^([^\s:]+):\s*(.*)$/)
          return nil if pairs.empty?
          headers = {}
          pairs.each do |pair|
            headers[pair.first] ||= []
            headers[pair.first] << pair.last.strip
          end
          headers
        end