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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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')