Runden(Python)

#!/usr/bin/env python
 
import sys
from decimal import *
 
# angenommen der dateiname kommt per kommandozeile
try:
        input = sys.argv[1]
        output = sys.argv[2]
        input = open(input)
        output = open(output, 'w')
        precision = Decimal (10) ** -2
        for line in input:
                wkn, kurs, zeit, _ = line.split(',')
                kurs = str( (Decimal(kurs)*Decimal("0.7693"))\
                                .quantize(precision)).replace('.',',')
                output.write("WKN=" + wkn + " Wert=" + kurs + " Euro\n")
except IndexError:
        print "usage:"
        print sys.argv[0] + " input ouptput"
        sys.exit(-1)
except IOError, err:
        print str(err)
        if type(input) == file and not input.closed: input.close()
        if type(output) == file and not output.closed: output.close()
        sys.exit(-1)
else:
        if not input.closed: input.close()
        if not output.closed: output.close()
        sys.exit(0)