Deletes a folder from the Exchange store. ::

      folder = service.folder().get_folder(id)
      print("Deleting folder: %s" % folder.display_name)
      folder.delete()

def delete(self):
    """
    Deletes a folder from the Exchange store. ::

      folder = service.folder().get_folder(id)
      print("Deleting folder: %s" % folder.display_name)
      folder.delete()
    """

    if not self.id:
      raise TypeError(u"You can't delete a folder that hasn't been created yet.")

    body = soap_request.delete_folder(self)

    response_xml = self.service.send(body)  # noqa
    # TODO: verify deletion
    self._id = None
    self._change_key = None

    return None