diff --git a/pkg/ip/ip.go b/pkg/ip/ip.go
index b46e9e8..fb1abd2 100644
--- a/pkg/ip/ip.go
+++ b/pkg/ip/ip.go
@@ -3,7 +3,6 @@
 package ip
 
 import (
-	"errors"
 	"fmt"
 	"net"
 	"net/http"
@@ -45,7 +44,7 @@ func NewChecker(trustedIPs []string) (*Checker, error) {
 // Contains checks if provided address is in the trusted IPs.
 func (ip *Checker) Contains(addr string) (bool, error) {
 	if len(addr) == 0 {
-		return false, errors.New("Contains:noAddress")
+		return false, fmt.Errorf("Contains:noAddress")
 	}
 
 	ipAddr, err := parseIP(addr)