Adds new resources to the event.

    *resources* can be a list of email addresses or :class:`ExchangeEventAttendee` objects.

def add_resources(self, resources):
    """
    Adds new resources to the event.

    *resources* can be a list of email addresses or :class:`ExchangeEventAttendee` objects.
    """
    new_resources = self._build_resource_dictionary(resources)

    for key in new_resources:
      self._resources[key] = new_resources[key]
    self._dirty_attributes.add(u'resources')