lib/amazon_flex_pay/model.rb
def format_value(val)
      case val
        when AmazonFlexPay::Model
        val.to_hash

        when Time
        val.utc.strftime('%Y-%m-%dT%H:%M:%SZ')

        when TrueClass, FalseClass
        val.to_s.capitalize

        when Array
        val.join(',')

        else
        val.to_s
      end
    end
def format_value(val)
      case val
        when AmazonFlexPay::Model
        val.to_hash

        when Time
        val.utc.strftime('%Y-%m-%dT%H:%M:%SZ')

        when TrueClass, FalseClass
        val.to_s.capitalize

        when Array
        val.join(',')

        else
        val.to_s
      end
    end
Formats times and booleans as Amazon desires them.