class Redis

def exists(*keys)
  if !Redis.exists_returns_integer && keys.size == 1
    if Redis.exists_returns_integer.nil?
      message = "`Redis#exists(key)` will return an Integer in redis-rb 4.3. `exists?` returns a boolean, you " \
        "should use it instead. To opt-in to the new behavior now you can set Redis.exists_returns_integer =  " \
        "true. To disable this message and keep the current (boolean) behaviour of 'exists' you can set " \
        "`Redis.exists_returns_integer = false`, but this option will be removed in 5.0. " \
        "(#{::Kernel.caller(1, 1).first})\n"
      ::Kernel.warn(message)
    end
    exists?(*keys)
  else
    _exists(*keys)
  end
end