”ceph health” Can not be used. Module 'restful' has failed dependency: No module named 'pecan'

Question

[root@stor1 ~]# ceph health
HEALTH_WARN Module 'restful' has failed dependency: No module named 'pecan'

but I have “pecan”

[root@stor1 ~]# pip3 list --format=columns | grep pecan
pecan           1.3.3  

I tried:
1. install this module for all nodes and monitor.
2. reboot all nodes.