old_contents: from ereuse_devicehub.resources.event.device.settings import EventSubSettingsMultipleDevices, EventWithDevices, \
      materialized_components
  
  
  class Sell(EventWithDevices):
      components = materialized_components
      components['materialized'] = True
      invoices = {
          'type': 'list',
          'schema': {
              'type': 'media',
              'accept': 'application/pdf'
          },
          'description': 'Upload invoices in PDF. You can select multiple by pressing Ctrl or Cmd.'
                         'You won\'t be able to modify them later and we will save them with the name they have.'
      }
      to = {
          'type': 'objectid',
          'data_relation': {
              'resource': 'accounts',
              'embeddable': True,
              'field': '_id'
          },
          'description': 'The user buying the devices.'
      }
      reserve = {
          'type': 'objectid',
          'data_relation': {
              'resource': 'events',
              'embeddable': True,
              'field': '_id'
          },
          'description': 'The reserve this sell confirms.'
      }
  
  
  class SellSettings(EventSubSettingsMultipleDevices):
      _schema = Sell
      fa = 'fa-money'
      sink = -5
      short_description = 'A successful selling.'
  
new_contents: from ereuse_devicehub.resources.event.device.settings import EventSubSettingsMultipleDevices, EventWithDevices, \
      materialized_components
  
  
  class Sell(EventWithDevices):
      components = materialized_components
      components['materialized'] = True
      invoiceNumber = {
          'type': 'string',
          'description': 'The id of your invoice so they can be linked.'
      }
      shippingDate = {
          'type': 'datetime',
          'description': 'When are the devices going to be ready for shipping?'
      }
      invoices = {
          'type': 'list',
          'schema': {
              'type': 'media',
              'accept': 'application/pdf'
          },
          'description': 'Upload invoices in PDF. You can select multiple by pressing Ctrl or Cmd.'
                         'You won\'t be able to modify them later and we will save them with the name they have.'
      }
      to = {
          'type': 'objectid',
          'data_relation': {
              'resource': 'accounts',
              'embeddable': True,
              'field': '_id'
          },
          'description': 'The user buying the devices.'
      }
      reserve = {
          'type': 'objectid',
          'data_relation': {
              'resource': 'events',
              'embeddable': True,
              'field': '_id'
          },
          'description': 'The reserve this sell confirms.'
      }
  
  
  class SellSettings(EventSubSettingsMultipleDevices):
      _schema = Sell
      fa = 'fa-money'
      sink = -5
      short_description = 'A successful selling.'
  
subject: Add invoiceNumber and shippingDate