python2.7-minimal (2.7.15-4ubuntu4~18.04) IndentationError: unexpected indent on apt-get dist-upgrade

When apt-get update, apt-get dist-upgrade run into this issue

# apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up python2.7-minimal (2.7.15-4ubuntu4~18.04) ...
Sorry: IndentationError: unexpected indent (sitecustomize.py, line 9)
dpkg: error processing package python2.7-minimal (--configure):
 installed python2.7-minimal package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of python2.7:
 python2.7 depends on python2.7-minimal (= 2.7.15-4ubuntu4~18.04); however:
  Package python2.7-minimal is not configured yet.

dpkg: error processing package python2.7 (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          Errors were encountered while processing:
 python2.7-minimal
 python2.7
E: Sub-process /usr/bin/dpkg returned an error code (1)

My system is:
# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.2 LTS
Release: 18.04
Codename: bionic

# dpkg --configure -a
produces similar output
Setting up python2.7-minimal (2.7.15-4ubuntu4~18.04) ...
Sorry: IndentationError: unexpected indent (sitecustomize.py, line 9)
dpkg: error processing package python2.7-minimal (--configure):
 installed python2.7-minimal package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of python2.7:
 python2.7 depends on python2.7-minimal (= 2.7.15-4ubuntu4~18.04); however:
  Package python2.7-minimal is not configured yet.

dpkg: error processing package python2.7 (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 python2.7-minimal
 python2.7

# apt-cache policy python2.7-minimal
python2.7-minimal:
  Installed: 2.7.15-4ubuntu4~18.04
  Candidate: 2.7.15-4ubuntu4~18.04
  Version table:
 *** 2.7.15-4ubuntu4~18.04 500
        500 http://ca.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     2.7.15~rc1-1ubuntu0.1 500
        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
     2.7.15~rc1-1 500
        500 http://ca.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

I expected python2.7-minimal to install without an indentation error

What happened was: Sorry: IndentationError: unexpected indent (sitecustomize.py, line 9)