diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 6c409d7..2901ea9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -14,6 +14,8 @@ jobs:
             bundler_version: 2.4.4
           - ruby: 3.0
             bundler_version: 2.4.4
+          - ruby: 2.7
+            bundler_version: 2.4.4
     env:
       CI: 1
       BUNDLER_VERSION: ${{ matrix.bundler_version }}
diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..050a1f3
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,2 @@
+AllCops:
+  TargetRubyVersion: 2.7
diff --git a/.standard.yml b/.standard.yml
index f31800f..518efa6 100644
--- a/.standard.yml
+++ b/.standard.yml
@@ -1,2 +1,4 @@
 fix: true
 format: progress
+extend_config:
+  - .rubocop.yml
diff --git a/lib/singed/kernel_ext.rb b/lib/singed/kernel_ext.rb
index f5b13eb..16cb266 100644
--- a/lib/singed/kernel_ext.rb
+++ b/lib/singed/kernel_ext.rb
@@ -1,7 +1,7 @@
 module Kernel
-  def flamegraph(label = nil, open: true, ignore_gc: false, interval: 1000, io: $stdout, &)
+  def flamegraph(label = nil, open: true, ignore_gc: false, interval: 1000, io: $stdout, &block)
     fg = Singed::Flamegraph.new(label: label, ignore_gc: ignore_gc, interval: interval)
-    result = fg.record(&)
+    result = fg.record(&block)
     fg.save
 
     # avoid a dep on a colorizing gem by doing this ourselves