diff --git a/bind/bind.go b/bind/bind.go
index b8a2b15..0d56827 100644
--- a/bind/bind.go
+++ b/bind/bind.go
@@ -40,12 +40,12 @@ func GenCPython(w io.Writer, fset *token.FileSet, pkg *Package) error {
 		return err
 	}
 
-	_, err = io.Copy(w, gen.decl.buf)
+	_, err = io.Copy(w, gen.decl)
 	if err != nil {
 		return err
 	}
 
-	_, err = io.Copy(w, gen.impl.buf)
+	_, err = io.Copy(w, gen.impl)
 	if err != nil {
 		return err
 	}
diff --git a/bind/printer.go b/bind/printer.go
index 0b3e058..786c27a 100644
--- a/bind/printer.go
+++ b/bind/printer.go
@@ -25,6 +25,10 @@ func (p *printer) writeIndent() error {
 	return err
 }
 
+func (p *printer) Read(b []byte) (n int, err error) {
+	return p.buf.Read(b)
+}
+
 func (p *printer) Write(b []byte) (n int, err error) {
 	wrote := 0
 	for len(b) > 0 {
diff --git a/bind/printer_test.go b/bind/printer_test.go
new file mode 100644
index 0000000..c533f39
--- /dev/null
+++ b/bind/printer_test.go
@@ -0,0 +1,57 @@
+// Copyright 2015 The go-python Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bind
+
+import (
+	"bytes"
+	"io"
+	"reflect"
+	"testing"
+)
+
+func TestPrinter(t *testing.T) {
+	decl := &printer{
+		buf:        new(bytes.Buffer),
+		indentEach: []byte("\t"),
+	}
+
+	impl := &printer{
+		buf:        new(bytes.Buffer),
+		indentEach: []byte("\t"),
+	}
+
+	decl.Printf("\ndecl 1\n")
+	decl.Indent()
+	decl.Printf(">>> decl-1\n")
+	decl.Outdent()
+	impl.Printf("impl 1\n")
+	decl.Printf("decl 2\n")
+	impl.Printf("impl 2\n")
+
+	out := new(bytes.Buffer)
+	_, err := io.Copy(out, decl)
+	if err != nil {
+		t.Fatalf("error: %v\n", err)
+	}
+
+	_, err = io.Copy(out, impl)
+	if err != nil {
+		t.Fatalf("error: %v\n", err)
+	}
+
+	want := `
+decl 1
+	>>> decl-1
+decl 2
+impl 1
+impl 2
+`
+
+	str := string(out.Bytes())
+	if !reflect.DeepEqual(str, want) {
+		t.Fatalf("error:\nwant=%q\ngot =%q\n", want, str)
+	}
+
+}