code: func (p *Plan) Format(color *colorstring.Colorize) string {
  	if p.Empty() {
  		return "This plan does nothing."
  	}
  
  	if color == nil {
  		color = &colorstring.Colorize{
  			Colors: colorstring.DefaultColors,
  			Reset:  false,
  		}
  	}
  
  	// Find the longest path length of all the paths that are changing,
  	// so we can align them all.
  	keyLen := 0
  	for _, r := range p.Resources {
  		for _, attr := range r.Attributes {
  			key := attr.Path
  
  			if len(key) > keyLen {
  				keyLen = len(key)
  			}
  		}
  	}
  
  	buf := new(bytes.Buffer)
  	for _, r := range p.Resources {
  		formatPlanInstanceDiff(buf, r, keyLen, color)
  	}
  
  	return strings.TrimSpace(buf.String())
  }
docs: // Format produces and returns a text representation of the receiving plan
  // intended for display in a terminal.
  //
  // If color is not nil, it is used to colorize the output.