# File lib/googleauth/default_credentials.rb, line 62
      def self.read_creds
        env_var = CredentialsLoader::ACCOUNT_TYPE_VAR
        type = ENV[env_var]
        raise "#{env_var} is undefined in env" unless type
        case type
        when "service_account"
          ServiceAccountCredentials
        when "authorized_user"
          UserRefreshCredentials
        else
          raise "credentials type '#{type}' is not supported"
        end
      end