class Selenium::WebDriver::Proxy

def initialize(opts = {})
  not_allowed = []
  opts.each do |k, v|
    if ALLOWED.key?(k)
      send(:"#{k}=", v)
    else
      not_allowed << k
    end
  end
  return if not_allowed.empty?
  raise ArgumentError, "unknown option#{'s' if not_allowed.size != 1}: #{not_allowed.inspect}"
end