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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ftp_get(fin_src, fout):
 """Download a file from an ftp server"""

    assert fin_src[:6] == 'ftp://', fin_src
    dir_full, fin_ftp = os.path.split(fin_src[6:])
    pt0 = dir_full.find('/')
    assert pt0 != -1, pt0
    ftphost = dir_full[:pt0]
    chg_dir = dir_full[pt0+1:]
    print('FTP RETR {HOST} {DIR} {SRC} -> {DST}'.format(
        HOST=ftphost, DIR=chg_dir, SRC=fin_ftp, DST=fout))
    ftp = FTP(ftphost)  # connect to host, default port      ftp.ncbi.nlm.nih.gov
    ftp.login()         # user anonymous, passwd anonymous@
    ftp.cwd(chg_dir)    # change into "debian" directory     gene/DATA
    cmd = 'RETR {F}'.format(F=fin_ftp)   #                   gene2go.gz
    ftp.retrbinary(cmd, open(fout, 'wb').write)  #           /usr/home/gene2go.gz
    ftp.quit()