import pgsanity.ecpg
pgsanity.ecpg.check_syntax(str)

>>> import pgsanity.ecpg
>>> pgsanity.ecpg.check_syntax("select * from;")
(True, '')
>>> pgsanity.ecpg.check_syntax("I am not SQL, am I?")
(True, '')
>>> pgsanity.ecpg.check_syntax("select select select select. select! select :-(")
(True, '')