# File lib/active_merchant/billing/gateways/paypal/paypal_common_api.rb, line 63
      def initialize(options = {})
        requires!(options, :login, :password)
        
        @options = {
          :pem => pem_file,
          :signature => signature
        }.update(options)
        
        if @options[:pem].blank? && @options[:signature].blank?
          raise ArgumentError, "An API Certificate or API Signature is required to make requests to PayPal" 
        end
        
        super
      end