[Biopython] BLAST database access

[xyz]

Hello,
I have run MegaBlast and the results I can parse for example with:

input_file = open("megablastres.txt","r")
for line in input_file.readlines():
    if line[0] == "#" :
        #header line, ignore
    else:
        parts = line.rstrip().split()
        print "Subject id = %s" % parts[1]

How could I retrieve the sequence which belong to subject id from BLAST 
database with BioPython?

Thank you in advance.

Best regards