code: def _find_usages_vpn_gateways(self):
          
  
          # 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'
          )
docs: find usage of vpn gateways