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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 _find_usages_vpn_gateways(self):
 """find usage of vpn gateways"""


        # do not include deleting and deleted in the results
        vpngws = self.conn.describe_vpn_gateways(Filters=[
            {
                'Name': 'state',
                'Values': [
                    'available',
                    'pending'
                ]
            }
        ])['VpnGateways']

        self.limits['Virtual private gateways']._add_current_usage(
            len(vpngws),
            aws_type='AWS::EC2::VPNGateway'
        )