# File lib/fog/aws/iam.rb, line 216
        def setup_credentials(options)
          @aws_access_key_id = options[:aws_access_key_id]
          existing_user = nil

          @root_access_key_id, _ = self.class.data.find { |_, d|
            d[:users].find { |_, user|
              existing_user = user[:access_keys].find { |key|
                key["AccessKeyId"] == @aws_access_key_id
              }
            }
          }

          @root_access_key_id ||= @aws_access_key_id
          @current_user_name = existing_user ? existing_user["UserName"] : "root"
        end