func New(arg string) Rope {
	if len(arg) == 0 {
		return emptyRope
	}
	return Rope{
		node: leaf(arg),
	}
}
New returns a Rope representing a given string.
package rope
import (
	"bytes"
	"errors"
	"fmt"
	"io"
)
var emptyRope = Rope{emptyNode}  
type Rope struct {
	node node  
}