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: keystore.rb
    path of file: ./repos/symmetric-encryption/lib/symmetric_encryption
    
    the code of the file until where you have to start completion: module SymmetricEncryption
  # Encryption keys are secured in Keystores
  module Keystore
    # @formatter:off
    autoload :Aws,         "symmetric_enc
    
    def self.constantize_symbol(symbol, namespace = "SymmetricEncryption::Keystore")
      klass = "#{namespace}::#{camelize(symbol.to_s)}"
      begin
        Object.const_get(klass)
      rescue NameError
        raise(ArgumentError, "Keystore: #{symbol.inspect} not found. Looking for: #{klass}")
      end