Refactor with RuboCop::RSpec::ExampleGroup

lib/rubocop/cop/rspec/let_setup.rb

@@ -57,27 +57,12 @@ def unused_let_bang(node)
         end
 
         def child_let_bang(node)
-          child_block_until_group(node) do |child|
-            node_with_name = let_bang(child)
+          RuboCop::RSpec::ExampleGroup.new(node).lets.each do |let|
+            node_with_name = let_bang(let)
 
             yield node_with_name if node_with_name
           end
         end
-
-        def child_block_until_group(node, &blk)
-          return unless node.body
-
-          unwrap_nested_begin(node).each_child_node(:block) do |child|
-            next if example_or_shared_group_or_including?(child)
-
-            yield child
-            child_block_until_group(child, &blk)
-          end
-        end
-
-        def unwrap_nested_begin(node)
-          node.body.begin_type? ? node.body : node
-        end
       end
     end
   end