diff --git a/eBook/exercises/chapter_6/error_returnval.go b/eBook/exercises/chapter_6/error_returnval.go
index dca2fbf..87a3ed2 100644
--- a/eBook/exercises/chapter_6/error_returnval.go
+++ b/eBook/exercises/chapter_6/error_returnval.go
@@ -1,44 +1,43 @@
 package main
 
 import (
-    "fmt"
-    "errors"
-    "math"
+	"errors"
+	"fmt"
+	"math"
 )
 
-
 func MySqrt1(a float64) (Sqrt float64, Err error) {
-    if a < 0 {
-        Err = errors.New("Fuck!")
-        Sqrt = 0
-        return
-    }
-    Sqrt = math.Sqrt(a)
-    return
+	if a < 0 {
+		Err = errors.New("Fuck!")
+		Sqrt = 0
+		return
+	}
+	Sqrt = math.Sqrt(a)
+	return
 }
 
 func MySqrt2(a float64) (float64, error) {
-    var Sqrt float64
-    var Err error
-    if a < 0 {
-        Err = errors.New("Fuck!")
-        Sqrt = 0
-        return Sqrt, Err
-    }
-    Sqrt = math.Sqrt(a)
-    return Sqrt, Err
+	var Sqrt float64
+	var Err error
+	if a < 0 {
+		Err = errors.New("Fuck!")
+		Sqrt = 0
+		return Sqrt, Err
+	}
+	Sqrt = math.Sqrt(a)
+	return Sqrt, Err
 }
 
 func main() {
-    var a float64 = 99.99
-    var b float64 = -99.99
-    Sqrt11, Err11 := MySqrt1(a)
-    Sqrt12, Err12 := MySqrt1(b)
-    Sqrt21, Err21 := MySqrt1(a)
-    Sqrt22, Err22 := MySqrt1(b)
+	var a float64 = 99.99
+	var b float64 = -99.99
+	Sqrt11, Err11 := MySqrt1(a)
+	Sqrt12, Err12 := MySqrt1(b)
+	Sqrt21, Err21 := MySqrt2(a)
+	Sqrt22, Err22 := MySqrt2(b)
 
-    fmt.Println(Sqrt11, Err11)
-    fmt.Println(Sqrt12, Err12)
-    fmt.Println(Sqrt21, Err21)
-    fmt.Println(Sqrt22, Err22)
-}
\ No newline at end of file
+	fmt.Println(Sqrt11, Err11)
+	fmt.Println(Sqrt12, Err12)
+	fmt.Println(Sqrt21, Err21)
+	fmt.Println(Sqrt22, Err22)
+}