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: flag_string_slice.go
    path of file: ./repos/buildkit/vendor/github.com/urfave/cli
    
    the code of the file until where you have to start completion: package cli

import (
	"flag"
	"fmt"
	"strings"
)

// StringSlice is an opaque type for []string to satisfy flag.Value and flag.Getter
type StringSlice []string

// Set appends the string value to the list of values
func (f *StringSlice) Set(value string) error {
	*f = append(*f, value)
	return nil
}

// String returns a readable representation of this value (for usage defaults)
func (f *StringSlice) String() string {
	return strings.Join(*f, ",")
}

// Value returns the slice of strings set by this flag
func (f *Stri
    
func (f StringSliceFlag) ApplyWithError(set *flag.FlagSet) error {
	if envVal, ok := flagFromFileEnv(f.FilePath, f.EnvVar); ok {
		newVal := &StringSlice{}
		for _, s := range strings.Split(envVal, ",") {
			s = strings.TrimSpace(s)
			if err := newVal.Set(s); err != nil {
				return fmt.Errorf("could not parse %s as string value for flag %s: %s", envVal, f.Name, err)
			}
		}
		if f.Value == nil {
			f.Value = newVal
		} else {
			*f.Value = *newVal
		}
	}

	eachName(f.Name, func(name string) {
		if f.Value == nil {
			f.Value = &StringSlice{}
		}
		set.Var(f.Value, name, f.Usage)
	})

	return nil
}