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: color.go
    path of file: ./repos/comply/vendor/github.com/juju/ansiterm
    
    the code of the file until where you have to start completion: // Copyright 2016 Canonical Ltd.
// Licensed under the LGPLv3, see LICENCE file for details.

package ansiterm

const (
	_ Color = iota
	Default
	Black
	Red
	Green
	Yellow
	Blue
	Magenta
	Cyan
	Gray
	DarkGray
	BrightRed
	BrightGr
    
func (c Color) foreground() attribute {
	switch c {
	case Default:
		return 39
	case Black:
		return 30
	case Red:
		return 31
	case Green:
		return 32
	case Yellow:
		return 33
	case Blue:
		return 34
	case Magenta:
		return 35
	case Cyan:
		return 36
	case Gray:
		return 37
	case DarkGray:
		return 90
	case BrightRed:
		return 91
	case BrightGreen:
		return 92
	case BrightYellow:
		return 93
	case BrightBlue:
		return 94
	case BrightMagenta:
		return 95
	case BrightCyan:
		return 96
	case White:
		return 97
	default:
		return unknownAttribute
	}
}