code: func AssertCertificateHasIPAddresses(t *testing.T, cert *x509.Certificate, IPAddresses ...net.IP) {
  	for _, IPAddress := range IPAddresses {
  		found := false
  		for _, val := range cert.IPAddresses {
  			if val.Equal(IPAddress) {
  				found = true
  				break
  			}
  		}
  
  		if !found {
  			t.Errorf("cert does not contain IPAddress %s", IPAddress)
  		}
  	}
  }
docs: // AssertCertificateHasIPAddresses is a utility function for kubeadm testing that asserts if a given certificate has
  // the expected IPAddresses