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: ingress_backend.go
    path of file: ./repos/rancher/pkg/schemas/mapper
    
    the code of the file until where you have to start completion: package mapper

import (
	"github.com/rancher/norman/types"
	"github.com/rancher/norman/types/values"
)

// These mappers copy data from the networking.k8s.io/v1-style Ingress fields
// to ex
    
func (i IngressBackend) ToInternal(data map[string]interface{}) error {
	if data != nil {
		serviceID := values.GetValueN(data, "serviceId")
		values.PutValue(data, serviceID, "serviceName")
		values.PutValue(data, serviceID, "service", "name")
		port := values.GetValueN(data, "targetPort")
		data["servicePort"] = port
		switch port.(type) {
		case int64:
			values.PutValue(data, port, "service", "port", "number")
		case string:
			values.PutValue(data, port, "service", "port", "name")
		}
	}
	return nil
}