Error writing the sqlite database file

[ganapatinatarajan]

I am using ubuntu 18.04 on Windows subsystem for linux/python 2.7 and sqlalchemy 0.7.
I am running the example on 17 atom LJ system:
from pele.systems import LJCluster
natoms=17
system=LJCluster(natoms)
database=system.create_database('lj17.sqlite')
bh=system.get_basinhopping(database)
bh.run(10)

Doing this writes an empty database file and gives the error below:
traceback (most recent call last):
File "bh.py", line 4, in
database=system.create_database('lj17.sqlite')
File "/home/gn203/.local/lib/python2.7/site-
packages/pele/systems/basesystem.py", line 234, in create_database
db = Database(**kwargs)
File "/home/gn203/.local/lib/python2.7/site-packages/pele/storage/database.py", line 432, in init
self._check_schema_version()
File "/home/gn203/.local/lib/python2.7/site-packages/pele/storage/database.py", line 477, in _check_schema_version
"%d (%d). Please use migrate_db.py in pele/scripts to update database"%(schema, _schema_version))
IOError: database schema outdated, current (newest) version: 0 (2). Please use migrate_db.py

Running migrate_db.py on the empty lj17.sqlite error file generates a further error:

current version: 0
newest version: 2
migrating from database version 0 to 1
Traceback (most recent call last):
File "/home/gn203/pkg/pele-master/scripts/migrate_db.py", line 63, in
migrate(dbfile)
File "/home/gn203/pkg/pele-master/scripts/migrate_db.py", line 47, in migrate
schema = migrate_script[schema](connection, schema)
File "/home/gn203/pkg/pele-master/scripts/migrate_db.py", line 13, in from_0_to_1
connection.execute("ALTER TABLE tbl_minima ADD fvib FLOAT;")
File "/home/gn203/.local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1294, in execute
params)
File "/home/gn203/.local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1471, in _execute_text
statement, parameters
File "/home/gn203/.local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1535, in _execute_context
context)
File "/home/gn203/.local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1528, in _execute_context
context)
File "/home/gn203/.local/lib/python2.7/site-packages/sqlalchemy/engine/default.py", line 325, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.OperationalError: (OperationalError) no such table: tbl_minima 'ALTER TABLE tbl_minima ADD fvib FLOAT;' ()