from ftplib import FTP
import os, sys, os.path

# Get accession number from argument
accession = sys.argv[1]
prefix = accession[0:2].uppercase()
middle = accession[3:5]
suffix = accession[6:8]

ftp = FTP('ftp.ncbi.nlm.nih.gov')

def handleDownload(block):
    file.write(block)
    
ftp.login()
ftp.cwd('/sra/sra-instant/reads/BySample/sra/