could not set customer data in CartCustomer

[alokumar1]

Specifications

• Version: 1.9.2.4
• Platform: ubuntu 18

I was trying to create an order so first i created a cart and then added product data then address the proceeded to add customer data but while setting it is giving me an error
my customer data is like this

{
                'firstname': 'testname,
                'lastname': 'testlast',
                'email': 'testemail@email.com',
                'mode': 'admin'
            }

so while runnig this i am getting error
client.cart_customer.set(2174529, customer_data)

  File "<stdin>", line 1, in <module>
  File "/home/python-magento/magento/checkout.py", line 168, in set
    [quote_id, customer_data, store_view])
  File "/home/python-magento/magento/api.py", line 202, in call
    return self.client.call(self.session, resource_path, arguments)
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1112, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1452, in __request
    verbose=self.__verbose
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1154, in request
    return self.single_request(host, handler, request_body, verbose)
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1170, in single_request
    return self.parse_response(resp)
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1342, in parse_response
    return u.close()
  File "/usr/lib/python3.6/xmlrpc/client.py", line 656, in close
    raise Fault(**self._stack[0])
xmlrpc.client.Fault: <Fault 1: 'Internal Error. Please see log for details.'>

How to resolve this and where to see logs? please help.