I am trying to install 6.1.2 on Debian 9.
python2 is default, python3 is also installed. MariaDB 10.2 installed.
Running setup-seafile-mysql.sh says it required python-mysqldb.
But it is already installed:
apt-get install python-mysqldb
Reading package lists... Done
Building dependency tree
Reading state information... Done
python-mysqldb is already the newest version (1.3.7-1.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded
./setup-seafile-mysql.sh
Checking python on this machine ...
Checking python moduln/Ubuntu:
e: setuptools ... Done.
Checking python module: python-imaging ... Done.
Checking python module: python-mysqldb ...
python-mysqldb is not installed, Please install it first.
On Debian/Ubuntu:
sudo apt-get install python-mysqldb
How to solve this? 
EDIT:
python setup-seafile-mysql.py
Traceback (most recent call last):
File "setup-seafile-mysql.py", line 20, in <module>
import MySQLdb
File "/usr/lib/python2.7/dist-packages/MySQLdb/__init__.py", line 19, in <module>
import _mysql
ImportError: /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18: version `libmariadbclient_18' not found (required by /usr/lib/python2.7/dist-packages/_mysql.x86_64-linux-gnu.so)
libmariadbclient18 is also installed.