Resends invites for an event.  ::

        event = service.calendar().get_event(id='KEY HERE')
        event.resend_invitations()

    Anybody who has not declined this meeting will get a new invite.

def resend_invitations(self):
    """
    Resends invites for an event.  ::

        event = service.calendar().get_event(id='KEY HERE')
        event.resend_invitations()

    Anybody who has not declined this meeting will get a new invite.
    """

    if not self.id:
      raise TypeError(u"You can't send invites for an event that hasn't been created yet.")

    # Under the hood, this is just an .update() but with no attributes changed.
    # We're going to enforce that by checking if there are any changed attributes and bail if there are
    if self._dirty_attributes:
      raise ValueError(u"There are unsaved changes to this invite - please update it first: %r" % self._dirty_attributes)

    self.refresh_change_key()
    body = soap_request.update_item(self, [], calendar_item_update_operation_type=u'SendOnlyToAll')
    self.service.send(body)

    return self