def get_all_placement_groups(self, groupnames=None, filters=None):
        """
        Get all placement groups associated with your account in a region.

        :type groupnames: list
        :param groupnames: A list of the names of placement groups to retrieve.
                           If not provided, all placement groups will be
                           returned.

        :type filters: dict
        :param filters: Optional filters that can be used to limit
                        the results returned.  Filters are provided
                        in the form of a dictionary consisting of
                        filter names as the key and filter values
                        as the value.  The set of allowable filter
                        names/values is dependent on the request
                        being performed.  Check the EC2 API guide
                        for details.

        :rtype: list
        :return: A list of :class:`boto.ec2.placementgroup.PlacementGroup`
        """
        params = {}
        if groupnames:
            self.build_list_params(params, groupnames, 'GroupName')
        if filters:
            self.build_filter_params(params, filters)
        return self.get_list('DescribePlacementGroups', params,
                             [('item', PlacementGroup)], verb='POST')