code: 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
docs: Formats times and booleans as Amazon desires them.