class Faraday::Middleware

def validate_default_options(options)
  invalid_keys = options.keys.reject { |opt| self::DEFAULT_OPTIONS.key?(opt) }
  return unless invalid_keys.any?
  raise(Faraday::InitializationError,
        "Invalid options provided. Keys not found in #{self}::DEFAULT_OPTIONS: #{invalid_keys.join(', ')}")
end