Here is a typical example for using readlines().
#!/usr/bin/env python
import traceback
import sys
fname = "/online_dir/" + "dbHostsTangoExplorer.lis"
try:
inp = open( fname, 'r')
except Exception as e:
print( " ", sys.exc_info()[0])
print( " ", e)
exc_type, exc_value, exc_traceback = sys.exc_info()
traceback.print_tb(exc_traceback, limit=None, file=sys.stdout)
sys.exit( 255)
dbHosts = []
for line in inp.readlines():
if line.strip().find( '#') == 0:
continue
dbHosts.append( line.strip())
inp.close()