old_contents: from zope.interface import implementer
  from plone.app.workflow.interfaces import ISharingPageRole
  from bda.plone.orders import permissions
  from bda.plone.orders import message_factory as _
  
  
  @implementer(ISharingPageRole)
  class VendorRole(object):
      title = _(u"title_is_vendor", default=u"Is Vendor")
      required_permission = permissions.DelegateVendorRole
  
new_contents: from zope.interface import implementer
  from plone.app.workflow.interfaces import ISharingPageRole
  from bda.plone.orders import permissions
  from bda.plone.orders import message_factory as _
  from bda.plone.orders.interfaces import IVendor
  
  
  @implementer(ISharingPageRole)
  class VendorRole(object):
      title = _(u"title_is_vendor", default=u"Is Vendor")
      required_permission = permissions.DelegateVendorRole
      required_interface = IVendor
  
subject: add required_interface