import xmlrpc.client

url ="localhost:8069"
db = "RDB"
username = "admin"
password = "admin"

common = xmlrpc.client.ServerProxy('{}/xmlrpc/2/common'.format(url))
print(common.version())

models = xmlrpc.client.ServerProxy('{}/xmlrpc/2/object'.format(url))
uid = common.authenticate(db, username, password, {})
print(uid)

getting this error 

Traceback (most recent call last):
File "C:/Users/Web Content/.PyCharmCE2019.3/config/scratches/scratch.py", line 12, in <module>
uid = common.authenticate(db, username, password, {})
File "C:\Users\Web Content\AppData\Local\Programs\Python\Python37\lib\xmlrpc\client.py", line 1112, in __call__
return self.__send(self.__name, args)
File "C:\Users\Web Content\AppData\Local\Programs\Python\Python37\lib\xmlrpc\client.py", line 1452, in __request
verbose=self.__verbose
File "C:\Users\Web Content\AppData\Local\Programs\Python\Python37\lib\xmlrpc\client.py", line 1154, in request
return self.single_request(host, handler, request_body, verbose)
File "C:\Users\Web Content\AppData\Local\Programs\Python\Python37\lib\xmlrpc\client.py", line 1170, in single_request
return self.parse_response(resp)
File "C:\Users\Web Content\AppData\Local\Programs\Python\Python37\lib\xmlrpc\client.py", line 1342, in parse_response
return u.close()
File "C:\Users\Web Content\AppData\Local\Programs\Python\Python37\lib\xmlrpc\client.py", line 656, in close
raise Fault(**self._stack[0])
xmlrpc.client.Fault: <Fault 1: 'Traceback (most recent call last):\n File "/odoo/odoo-server/odoo/modules/registry.py", line 59, in __new__\n return cls.registries[db_name]\n File "/odoo/odoo-server/odoo/tools/func.py", line 69, in wrapper\n return func(self, *args, **kwargs)\n File "/odoo/odoo-server/odoo/tools/lru.py", line 44, in __getitem__\n a = self.d[obj].me\nKeyError: \'pnv3\'\n\nDuring handling of the above exception, another exception occurred:\n\nTraceback (most recent call last):\n File "/odoo/odoo-server/odoo/addons/base/controllers/rpc.py", line 63, in xmlrpc_2\n response = self._xmlrpc(service)\n File "/odoo/odoo-server/odoo/addons/base/controllers/rpc.py", line 43, in _xmlrpc\n result = dispatch_rpc(service, method, params)\n File "/odoo/odoo-server/odoo/http.py", line 138, in dispatch_rpc\n result = dispatch(method, params)\n File "/odoo/odoo-server/odoo/service/common.py", line 61, in dispatch\n return g[exp_method_name](*params)\n File "/odoo/odoo-server/odoo/service/common.py", line 30, in exp_authenticate\n res_users = odoo.registry(db)[\'res.users\']\n File "/odoo/odoo-server/odoo/__init__.py", line 104, in registry\n return modules.registry.Registry(database_name)\n File "/odoo/odoo-server/odoo/modules/registry.py", line 61, in __new__\n return cls.new(db_name)\n File "/odoo/odoo-server/odoo/modules/registry.py", line 73, in new\n registry.init(db_name)\n File "/odoo/odoo-server/odoo/modules/registry.py", line 141, in init\n with closing(self.cursor()) as cr:\n File "/odoo/odoo-server/odoo/modules/registry.py", line 492, in cursor\n return self._db.cursor()\n File "/odoo/odoo-server/odoo/sql_db.py", line 649, in cursor\n return Cursor(self.__pool, self.dbname, self.dsn, serialized=serialized)\n File "/odoo/odoo-server/odoo/sql_db.py", line 186, in __init__\n self._cnx = pool.borrow(dsn)\n File "/odoo/odoo-server/odoo/sql_db.py", line 532, in _locked\n return fun(self, *args, **kwargs)\n File "/odoo/odoo-server/odoo/sql_db.py", line 600, in borrow\n **connection_info)\n File "/usr/local/lib/python3.7/dist-packages/psycopg2/__init__.py", line 130, in connect\n conn = _connect(dsn, connection_factory=connection_factory, **kwasync)\npsycopg2.OperationalError: FATAL: database "pnv3" does not exist\n\n'>