class Selenium::WebDriver::Proxy

def type=(type)
  unless TYPES.key? type
    raise ArgumentError,
          "invalid proxy type: #{type.inspect}, expected one of #{TYPES.keys.inspect}"
  end
  if defined?(@type) && type != @type
    raise ArgumentError, "incompatible proxy type #{type.inspect} (already set to #{@type.inspect})"
  end
  @type = type
end