diff --git a/README.md b/README.md
index 8e1c420..c91f208 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Курс по Го в ШАД
 
-Для работы с кодом нужен go 1.17 или выше.
+Для работы с кодом нужен go 1.18 или выше.
 
 ```sh
 git clone https://gitlab.com/slon/shad-go.git
diff --git a/allocs/allocs.go b/allocs/allocs.go
index 86fa416..40aa5ed 100644
--- a/allocs/allocs.go
+++ b/allocs/allocs.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package allocs
 
diff --git a/allocs/baseline.go b/allocs/baseline.go
index 402aef7..9519382 100644
--- a/allocs/baseline.go
+++ b/allocs/baseline.go
@@ -1,5 +1,4 @@
 //go:build !solution && !change
-// +build !solution,!change
 
 package allocs
 
diff --git a/batcher/batcher.go b/batcher/batcher.go
index 7cc4901..84440cb 100644
--- a/batcher/batcher.go
+++ b/batcher/batcher.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package batcher
 
diff --git a/batcher/batcher_race_test.go b/batcher/batcher_race_test.go
index 0f361a6..1ac9f40 100644
--- a/batcher/batcher_race_test.go
+++ b/batcher/batcher_race_test.go
@@ -1,5 +1,4 @@
 //go:build race
-// +build race
 
 package batcher
 
diff --git a/batcher/slow/value.go b/batcher/slow/value.go
index 00f7f48..e2e1041 100644
--- a/batcher/slow/value.go
+++ b/batcher/slow/value.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package slow
 
diff --git a/blowfish/blowfish.go b/blowfish/blowfish.go
index 28a055f..12b0890 100644
--- a/blowfish/blowfish.go
+++ b/blowfish/blowfish.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package blowfish
 
diff --git a/build.docker b/build.docker
index 1b65e25..86a104c 100644
--- a/build.docker
+++ b/build.docker
@@ -1,10 +1,10 @@
-FROM golang:1.17
+FROM golang:1.18
 
 RUN apt-get update && apt-get install -y \
     rsync libssl-dev postgresql sudo redis-server \
  && rm -rf /var/lib/apt/lists/*
 
-RUN curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.44.0
+RUN curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.45.2
 RUN curl -L "https://github.com/docker/compose/releases/download/1.28.5/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
 RUN chmod +x /usr/local/bin/docker-compose
 RUN curl -fsSL https://get.docker.com | sh
diff --git a/ciletters/letter.go b/ciletters/letter.go
index c5246ad..4130454 100644
--- a/ciletters/letter.go
+++ b/ciletters/letter.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package ciletters
 
diff --git a/ciletters/notification.go b/ciletters/notification.go
index 61978e4..4c7d09f 100644
--- a/ciletters/notification.go
+++ b/ciletters/notification.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package ciletters
 
diff --git a/cond/cond.go b/cond/cond.go
index 4d74c93..68adbc8 100644
--- a/cond/cond.go
+++ b/cond/cond.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package cond
 
diff --git a/coverme/app/app.go b/coverme/app/app.go
index 22d39b6..4deb8ad 100644
--- a/coverme/app/app.go
+++ b/coverme/app/app.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package app
 
diff --git a/coverme/app/coverage_test.go b/coverme/app/coverage_test.go
index 66b10f5..7f957c9 100644
--- a/coverme/app/coverage_test.go
+++ b/coverme/app/coverage_test.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package app
 
diff --git a/coverme/client/client.go b/coverme/client/client.go
index b3bbe22..93df2f9 100644
--- a/coverme/client/client.go
+++ b/coverme/client/client.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package client
 
diff --git a/coverme/main.go b/coverme/main.go
index 2c97450..25262af 100644
--- a/coverme/main.go
+++ b/coverme/main.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package main
 
diff --git a/coverme/models/storage.go b/coverme/models/storage.go
index c4fc981..2459c61 100644
--- a/coverme/models/storage.go
+++ b/coverme/models/storage.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package models
 
diff --git a/coverme/models/todo.go b/coverme/models/todo.go
index 80ce420..3e3ba52 100644
--- a/coverme/models/todo.go
+++ b/coverme/models/todo.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package models
 
diff --git a/coverme/utils/httputils.go b/coverme/utils/httputils.go
index f052723..7cea454 100644
--- a/coverme/utils/httputils.go
+++ b/coverme/utils/httputils.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package utils
 
diff --git a/digitalclock/main.go b/digitalclock/main.go
index 375bf63..2a10cda 100644
--- a/digitalclock/main.go
+++ b/digitalclock/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/digitalclock/symbols.go b/digitalclock/symbols.go
index 6593e32..0a33dd9 100644
--- a/digitalclock/symbols.go
+++ b/digitalclock/symbols.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package main
 
diff --git a/distbuild/pkg/api/build_client.go b/distbuild/pkg/api/build_client.go
index 77661a2..dbd42ae 100644
--- a/distbuild/pkg/api/build_client.go
+++ b/distbuild/pkg/api/build_client.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package api
 
diff --git a/distbuild/pkg/api/build_handler.go b/distbuild/pkg/api/build_handler.go
index a682d15..0606c53 100644
--- a/distbuild/pkg/api/build_handler.go
+++ b/distbuild/pkg/api/build_handler.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package api
 
diff --git a/distbuild/pkg/api/heartbeat_client.go b/distbuild/pkg/api/heartbeat_client.go
index 7306b93..105aab4 100644
--- a/distbuild/pkg/api/heartbeat_client.go
+++ b/distbuild/pkg/api/heartbeat_client.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package api
 
diff --git a/distbuild/pkg/api/heartbeat_handler.go b/distbuild/pkg/api/heartbeat_handler.go
index a475d2d..8daaf16 100644
--- a/distbuild/pkg/api/heartbeat_handler.go
+++ b/distbuild/pkg/api/heartbeat_handler.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package api
 
diff --git a/distbuild/pkg/artifact/cache.go b/distbuild/pkg/artifact/cache.go
index a328cf8..0d69c9d 100644
--- a/distbuild/pkg/artifact/cache.go
+++ b/distbuild/pkg/artifact/cache.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package artifact
 
diff --git a/distbuild/pkg/artifact/client.go b/distbuild/pkg/artifact/client.go
index 057ed7d..2ae9e9d 100644
--- a/distbuild/pkg/artifact/client.go
+++ b/distbuild/pkg/artifact/client.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package artifact
 
diff --git a/distbuild/pkg/artifact/handler.go b/distbuild/pkg/artifact/handler.go
index e12059f..34c65c4 100644
--- a/distbuild/pkg/artifact/handler.go
+++ b/distbuild/pkg/artifact/handler.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package artifact
 
diff --git a/distbuild/pkg/client/build.go b/distbuild/pkg/client/build.go
index 7a34487..8d018e1 100644
--- a/distbuild/pkg/client/build.go
+++ b/distbuild/pkg/client/build.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package client
 
diff --git a/distbuild/pkg/dist/coordinator.go b/distbuild/pkg/dist/coordinator.go
index 0dd7315..544762d 100644
--- a/distbuild/pkg/dist/coordinator.go
+++ b/distbuild/pkg/dist/coordinator.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package dist
 
diff --git a/distbuild/pkg/filecache/client.go b/distbuild/pkg/filecache/client.go
index 6468ace..2840816 100644
--- a/distbuild/pkg/filecache/client.go
+++ b/distbuild/pkg/filecache/client.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package filecache
 
diff --git a/distbuild/pkg/filecache/filecache.go b/distbuild/pkg/filecache/filecache.go
index 7d0ac8a..768f17f 100644
--- a/distbuild/pkg/filecache/filecache.go
+++ b/distbuild/pkg/filecache/filecache.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package filecache
 
diff --git a/distbuild/pkg/filecache/handler.go b/distbuild/pkg/filecache/handler.go
index 6a948df..4a271f3 100644
--- a/distbuild/pkg/filecache/handler.go
+++ b/distbuild/pkg/filecache/handler.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package filecache
 
diff --git a/distbuild/pkg/scheduler/scheduler.go b/distbuild/pkg/scheduler/scheduler.go
index 2b1a9f9..e026024 100644
--- a/distbuild/pkg/scheduler/scheduler.go
+++ b/distbuild/pkg/scheduler/scheduler.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package scheduler
 
diff --git a/distbuild/pkg/tarstream/stream.go b/distbuild/pkg/tarstream/stream.go
index 114d12a..b4d760b 100644
--- a/distbuild/pkg/tarstream/stream.go
+++ b/distbuild/pkg/tarstream/stream.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package tarstream
 
diff --git a/distbuild/pkg/worker/worker.go b/distbuild/pkg/worker/worker.go
index d9884b8..af06d12 100644
--- a/distbuild/pkg/worker/worker.go
+++ b/distbuild/pkg/worker/worker.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package worker
 
diff --git a/dupcall/dupcall.go b/dupcall/dupcall.go
index c382e1f..9a848b7 100644
--- a/dupcall/dupcall.go
+++ b/dupcall/dupcall.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package dupcall
 
diff --git a/externalsort/io.go b/externalsort/io.go
index 012c13a..5874ea3 100644
--- a/externalsort/io.go
+++ b/externalsort/io.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package externalsort
 
diff --git a/externalsort/sort.go b/externalsort/sort.go
index 3bf00a9..b9c05b3 100644
--- a/externalsort/sort.go
+++ b/externalsort/sort.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package externalsort
 
diff --git a/fetchall/main.go b/fetchall/main.go
index 375bf63..2a10cda 100644
--- a/fetchall/main.go
+++ b/fetchall/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/fetchall/main_test.go b/fetchall/main_test.go
index b63d0f4..22ba64a 100644
--- a/fetchall/main_test.go
+++ b/fetchall/main_test.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package main
 
diff --git a/fileleak/fileleak.go b/fileleak/fileleak.go
index 3813928..1dd423b 100644
--- a/fileleak/fileleak.go
+++ b/fileleak/fileleak.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package fileleak
 
diff --git a/firewall/cmd/firewall/main.go b/firewall/cmd/firewall/main.go
index 375bf63..2a10cda 100644
--- a/firewall/cmd/firewall/main.go
+++ b/firewall/cmd/firewall/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/firewall/cmd/service/main.go b/firewall/cmd/service/main.go
index 695086b..b59a053 100644
--- a/firewall/cmd/service/main.go
+++ b/firewall/cmd/service/main.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package main
 
diff --git a/forth/eval.go b/forth/eval.go
index 35bd347..e0b5d66 100644
--- a/forth/eval.go
+++ b/forth/eval.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/forth/main.go b/forth/main.go
index c1a87d1..63299ec 100644
--- a/forth/main.go
+++ b/forth/main.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package main
 
diff --git a/gitfame/cmd/gitfame/main.go b/gitfame/cmd/gitfame/main.go
index 375bf63..2a10cda 100644
--- a/gitfame/cmd/gitfame/main.go
+++ b/gitfame/cmd/gitfame/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/go.mod b/go.mod
index aa5c5f7..15928df 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module gitlab.com/slon/shad-go
 
-go 1.17
+go 1.18
 
 require (
 	github.com/ClickHouse/clickhouse-go v1.4.0
diff --git a/hogwarts/courselist.go b/hogwarts/courselist.go
index 8b8750d..34ea140 100644
--- a/hogwarts/courselist.go
+++ b/hogwarts/courselist.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package hogwarts
 
diff --git a/hotelbusiness/hotels.go b/hotelbusiness/hotels.go
index d11e980..e0214e8 100644
--- a/hotelbusiness/hotels.go
+++ b/hotelbusiness/hotels.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package hotelbusiness
 
diff --git a/illegal/field.go b/illegal/field.go
index 84eb2d0..40d2634 100644
--- a/illegal/field.go
+++ b/illegal/field.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package illegal
 
diff --git a/illegal/internal/struct.go b/illegal/internal/struct.go
index 5023f2f..c09a1b3 100644
--- a/illegal/internal/struct.go
+++ b/illegal/internal/struct.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package internal
 
diff --git a/illegal/string.go b/illegal/string.go
index 3f12b3b..2ead743 100644
--- a/illegal/string.go
+++ b/illegal/string.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package illegal
 
diff --git a/jsonlist/jsonlist.go b/jsonlist/jsonlist.go
index 8eba2c8..98b51e3 100644
--- a/jsonlist/jsonlist.go
+++ b/jsonlist/jsonlist.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package jsonlist
 
diff --git a/jsonrpc/jsonrpc.go b/jsonrpc/jsonrpc.go
index 5ec415e..1fe22be 100644
--- a/jsonrpc/jsonrpc.go
+++ b/jsonrpc/jsonrpc.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package jsonrpc
 
diff --git a/keylock/keylock.go b/keylock/keylock.go
index 7e21132..7515ffb 100644
--- a/keylock/keylock.go
+++ b/keylock/keylock.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package keylock
 
diff --git a/lectures/07-sql/hasql/open.go b/lectures/07-sql/hasql/open.go
index bfc1427..bdc1e51 100644
--- a/lectures/07-sql/hasql/open.go
+++ b/lectures/07-sql/hasql/open.go
@@ -1,7 +1,10 @@
 package hasql
 
 import (
+	"context"
+	"database/sql"
 	"log"
+	"time"
 
 	_ "github.com/jackc/pgx/v4/stdlib"
 	"golang.yandex/hasql"
@@ -24,7 +27,7 @@ func Open() {
 		log.Fatal(err)
 	}
 
-	log.Println("Node address", node.Addr)
+	log.Println("Node address", node.Addr())
 
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
diff --git a/lectures/07-sql/redis/redis.go b/lectures/07-sql/redis/redis.go
index fb42014..28d956c 100644
--- a/lectures/07-sql/redis/redis.go
+++ b/lectures/07-sql/redis/redis.go
@@ -1,6 +1,7 @@
 package redis
 
 import (
+	"context"
 	"log"
 	"time"
 
diff --git a/lrucache/cache.go b/lrucache/cache.go
index 043dec7..d0f55af 100644
--- a/lrucache/cache.go
+++ b/lrucache/cache.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package lrucache
 
diff --git a/lrucache/lru.go b/lrucache/lru.go
index 357968d..7cdaedc 100644
--- a/lrucache/lru.go
+++ b/lrucache/lru.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package lrucache
 
diff --git a/olympics/main.go b/olympics/main.go
index 375bf63..2a10cda 100644
--- a/olympics/main.go
+++ b/olympics/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/once/once.go b/once/once.go
index 28d206f..eec3c92 100644
--- a/once/once.go
+++ b/once/once.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package once
 
diff --git a/otp/cipher.go b/otp/cipher.go
index dafcb2f..993ab22 100644
--- a/otp/cipher.go
+++ b/otp/cipher.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package otp
 
diff --git a/pubsub/my_pubsub.go b/pubsub/my_pubsub.go
index 81b7d6a..9ab8cc2 100644
--- a/pubsub/my_pubsub.go
+++ b/pubsub/my_pubsub.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package pubsub
 
diff --git a/pubsub/pubsub.go b/pubsub/pubsub.go
index cae3565..0c68472 100644
--- a/pubsub/pubsub.go
+++ b/pubsub/pubsub.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package pubsub
 
diff --git a/ratelimit/ratelimit.go b/ratelimit/ratelimit.go
index 8ebca19..1c2a2f5 100644
--- a/ratelimit/ratelimit.go
+++ b/ratelimit/ratelimit.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package ratelimit
 
diff --git a/retryupdate/kvapi/api.go b/retryupdate/kvapi/api.go
index 0ce5bae..f05b61e 100644
--- a/retryupdate/kvapi/api.go
+++ b/retryupdate/kvapi/api.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package kvapi
 
diff --git a/retryupdate/kvapi/errors.go b/retryupdate/kvapi/errors.go
index 28599d2..a5920a9 100644
--- a/retryupdate/kvapi/errors.go
+++ b/retryupdate/kvapi/errors.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package kvapi
 
diff --git a/retryupdate/update.go b/retryupdate/update.go
index 42ade37..a404f18 100644
--- a/retryupdate/update.go
+++ b/retryupdate/update.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package retryupdate
 
diff --git a/reversemap/reversemap.go b/reversemap/reversemap.go
index b7a99cc..0572a70 100644
--- a/reversemap/reversemap.go
+++ b/reversemap/reversemap.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package reversemap
 
diff --git a/rwmutex/rwmutex.go b/rwmutex/rwmutex.go
index 2a7b561..4156b5e 100644
--- a/rwmutex/rwmutex.go
+++ b/rwmutex/rwmutex.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package rwmutex
 
diff --git a/speller/speller.go b/speller/speller.go
index 0e4d114..b1f50f5 100644
--- a/speller/speller.go
+++ b/speller/speller.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package speller
 
diff --git a/structtags/structtags.go b/structtags/structtags.go
index 091f952..b2e8625 100644
--- a/structtags/structtags.go
+++ b/structtags/structtags.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package structtags
 
diff --git a/sum/sum.go b/sum/sum.go
index 3ae5e2d..1da0e52 100644
--- a/sum/sum.go
+++ b/sum/sum.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package sum
 
diff --git a/tabletest/coverage_test.go b/tabletest/coverage_test.go
index 6fc9f69..34d85dc 100644
--- a/tabletest/coverage_test.go
+++ b/tabletest/coverage_test.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package tabletest
 
diff --git a/tabletest/parse_duration.go b/tabletest/parse_duration.go
index f60fe08..af46f1b 100644
--- a/tabletest/parse_duration.go
+++ b/tabletest/parse_duration.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package tabletest
 
diff --git a/testequal/assertions.go b/testequal/assertions.go
index b73260f..1f4a1b1 100644
--- a/testequal/assertions.go
+++ b/testequal/assertions.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package testequal
 
diff --git a/testequal/t.go b/testequal/t.go
index 0d485cf..9d96c41 100644
--- a/testequal/t.go
+++ b/testequal/t.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package testequal
 
diff --git a/testifycheck/testifycheck.go b/testifycheck/testifycheck.go
index d7886bc..3cd5400 100644
--- a/testifycheck/testifycheck.go
+++ b/testifycheck/testifycheck.go
@@ -1,4 +1,3 @@
 //go:build !solution
-// +build !solution
 
 package testifycheck
diff --git a/tools/testtool/buildtags.go b/tools/testtool/buildtags.go
index a9d9de3..464aea1 100644
--- a/tools/testtool/buildtags.go
+++ b/tools/testtool/buildtags.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package testtool
 
diff --git a/tparallel/tparallel.go b/tparallel/tparallel.go
index a1bd395..56091a1 100644
--- a/tparallel/tparallel.go
+++ b/tparallel/tparallel.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package tparallel
 
diff --git a/urlfetch/main.go b/urlfetch/main.go
index 375bf63..2a10cda 100644
--- a/urlfetch/main.go
+++ b/urlfetch/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/urlfetch/main_test.go b/urlfetch/main_test.go
index e535134..c02af54 100644
--- a/urlfetch/main_test.go
+++ b/urlfetch/main_test.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package main
 
diff --git a/urlshortener/main.go b/urlshortener/main.go
index 375bf63..2a10cda 100644
--- a/urlshortener/main.go
+++ b/urlshortener/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/utf8/reverse/reverse.go b/utf8/reverse/reverse.go
index 885ff35..38d066c 100644
--- a/utf8/reverse/reverse.go
+++ b/utf8/reverse/reverse.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package reverse
 
diff --git a/utf8/spacecollapse/collapse.go b/utf8/spacecollapse/collapse.go
index 34b21b8..2af1244 100644
--- a/utf8/spacecollapse/collapse.go
+++ b/utf8/spacecollapse/collapse.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package spacecollapse
 
diff --git a/varfmt/fmt.go b/varfmt/fmt.go
index 50396c1..b093e45 100644
--- a/varfmt/fmt.go
+++ b/varfmt/fmt.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package varfmt
 
diff --git a/varjoin/join.go b/varjoin/join.go
index 39e658f..e58f5ca 100644
--- a/varjoin/join.go
+++ b/varjoin/join.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package varjoin
 
diff --git a/waitgroup/waitgroup.go b/waitgroup/waitgroup.go
index 6925be0..5d2b14a 100644
--- a/waitgroup/waitgroup.go
+++ b/waitgroup/waitgroup.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package waitgroup
 
diff --git a/wordcount/main.go b/wordcount/main.go
index 375bf63..2a10cda 100644
--- a/wordcount/main.go
+++ b/wordcount/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main
 
diff --git a/wordcount/main_test.go b/wordcount/main_test.go
index f29734c..41ddb80 100644
--- a/wordcount/main_test.go
+++ b/wordcount/main_test.go
@@ -1,5 +1,4 @@
 //go:build !change
-// +build !change
 
 package main
 
diff --git a/wscat/main.go b/wscat/main.go
index 375bf63..2a10cda 100644
--- a/wscat/main.go
+++ b/wscat/main.go
@@ -1,5 +1,4 @@
 //go:build !solution
-// +build !solution
 
 package main