from_buffer() cannot return the address of the raw string within a str or unicode or bytearray object (HTTP 400) edit

[DFazeli]

hi all.
During executing

openstack project create --domain default --description "Service Project" service

for config keyston on controller by this tutorial :

https://docs.openstack.org/keystone/pike/install/keystone-users-ubuntu.html

i get this error

from_buffer() cannot return the address of the raw string within a str or unicode or bytearray object (HTTP 400).

please guide me Why this error occurs?