executing a sql script

I'm using python and can execute standard "select,update,delete,functions".
What I'd like to do is execute a sql script (a text file). But I don't know
how?
Some thing like:
import psycopg2
import psycopg2.extensions
conn = psycopg2.connect("host=%s dbname=%s user =%s password
=%s " %(self.pgSqlHostID.Value,self.pgSqlDatabaseID.Value,self.pgSqlUserID.Value,self.msSqlPasswordID.Value))

conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
tempCursor= conn.cursor()
try:
tempCursor.execute("run script %s " % FileNameScript)
tempCursor.execute('commit')
--
John Fabiani