Cooking Converter Project V1.0

# Cooking Converter Project V1.0
# <ha>import antigravity http://xkcd.com/353/</ha>

while True: # clear the screen
    if sys.platform.startswith('win'):
        import os
        os.system('cls')
        break
    elif sys.platform.startswith('linux'):
        import os
        os.system('clear')
        break

print "What is the amount you are converting from?"
in_amount = int(raw_input(">"))

print "\nWhat is the unit you are converting from:"
print "gram | tbsp | tsp | ml | lt | oz | pnt | cup | qrt | gal? "
in_unit = raw_input(">")

print "\nFinally, what is the unit you are converting to:"
print "gram | tbsp | tsp | ml | lt | oz | pnt | cup | qrt | gal? "
out_unit = raw_input(">")


# all related to the gram
# volmul = volume_unit_multiplier
def convert(in_amount, in_unit, out_unit):
    volmul = {
        'gram': 1,
        'tbsp': 14.8,
        'tsp' : 4.2,
        'ml'  : 1,
        'lt'  : 1000.,
        'pnt' : 473.2,
        'cup' : 236.5,
        'qrt' : 946.3,
        'gal' : 3785,
        'oz'  : 28.34
}
    return in_amount*volmul[in_unit]/volmul[out_unit]

print "\n%.2f %s\n" % (convert(in_amount, in_unit, out_unit), out_unit)