func StringSlice(val, sep string) ([]string, error) {
	return strings.Split(val, sep), nil
}
StringSlice converts 'val' where individual strings are separated by
'sep' into a string slice.
package runtime
import (
	"encoding/base64"
	"fmt"
	"strconv"
	"strings"
	"github.com/golang/protobuf/jsonpb"
	"github.com/golang/protobuf/ptypes/duration"
	"github.com/golang/protobuf/ptypes/timestamp"
	"github.com/golang/protobuf/ptypes/wrappers"
)
func String(val string) (string, error) {
	return val, nil
}