You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: get_token.go
    path of file: ./repos/kubelogin/pkg/usecases/credentialplugin
    
    the code of the file until where you have to start completion: // Package credentialplugin provides the use-cases for running as a client-go credentials plugin.

    
func extractBindAddressPorts(o *authcode.BrowserOption) []string {
	if o == nil {
		return nil
	}
	var ports []string
	for _, addr := range o.BindAddress {
		_, port, err := net.SplitHostPort(addr)
		if err != nil {
			return nil // invalid address
		}
		if port == "0" {
			return nil // any port
		}
		ports = append(ports, port)
	}
	return ports
}