```ruby
class Kst
  include Cinch::Plugin

  match /(kst)$/, prefix: /^(\.)/
  match /(help kst)$/, method: :help, prefix: /^(\.)/

  def execute(m)
    utc = Time.now.utc
    kst = utc + (9 * 3600)
    time = kst.strftime("%F %H:%M KST")
    m.reply "#{time}"
  end

  def help(m)
    m.reply 'returns date and time (KST)'
  end

end
```

Remove date, time, and string interpolation
user
```ruby
class Kst
  include Cinch::Plugin

  match /(kst)$/, prefix: /^(\.)/
  match /(help kst)$/, method: :help, prefix: /^(\.)/

  def execute(m)
    utc = Time.now.utc
    kst = utc + (9 * 3600)
    time = kst.strftime("%F %H:%M KST")
    m.reply time
  end

  def help(m)
    m.reply 'returns date and time (KST)'
  end

end
```
assistant