func AddImport(fset *token.FileSet, f *ast.File, path string) (added bool) {
	return AddNamedImport(fset, f, "", path)
}
AddImport adds the import path to the file f, if absent.
package astutil  
import (
	"fmt"
	"go/ast"
	"go/token"
	"strconv"
	"strings"
)