# UltracartClient::EmailPerformanceCustomerHistogram ## Properties | Name | Type | Description | Notes | | ---- | ---- | ----------- | ----- | | **periods** | [**Array<EmailPerformanceCustomerHistogramPeriod>**](EmailPerformanceCustomerHistogramPeriod.md) | Periods (newest to oldest) | [optional] | ## Example ```ruby require 'ultracart_api' instance = UltracartClient::EmailPerformanceCustomerHistogram.new( periods: null ) ```