cooking converter

cook.py

# Cooking Converter Project Ver1.03
"""Changelog
ver1.03
- removed clearscreen function for now
- units now print full names
- script gives plural unit when necessary
- fractions implemented but not printing human-readable
"""

from __future__ import division
from fractions import Fraction
import math

"""Maps unit abbreviations to their full names."""
metric_units_dict = {
    "gram" : "gram",
    "ml"   : "milliliter",
    "lt"   : "liter",
    "oz"   : "ounce",
    "pnt"  : "pint",
    "qrt"  : "quart",
    "gal"  : "gallon"
}

imperial_units_dict = {
    "tsp"  : "teaspoon",
    "tbsp" : "tablespoon",
    "cup"  : "cup",
    "lb"   : "pound"
}

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

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

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

"""Takes the user input and finds the full unit-out name."""
#full_unitout_name = units_dict.get(out_unit, "Not found")
full_unitout_name = metric_units_dict.get(out_unit, imperial_units_dict.get(out_unit, "Not found"))

"""Converts the given amount to the desired unit."""
# all units given in relation to the gram.
def unit_conversion(in_amount, in_unit, out_unit):
    unit_multiplier = {
        'gram': 1.,
        'ml'  : 1.,
        'lt'  : 1000.,
        'tsp' : 4.2,
        'tbsp': 14.8,
        'oz'  : 28.34,
        'cup' : 236.5,
        'pnt' : 473.2,
        'qrt' : 946.3,
        'gal' : 3785.,
        'lb'  : 453.6,
    }

    return in_amount*unit_multiplier[in_unit]/unit_multiplier[out_unit]


converted = unit_conversion(in_amount, in_unit, out_unit)

"""Appends and 's' to a solution > 1."""
def pluralize_unit():
    if converted > 1.0:
        return full_unitout_name  + 's'
    else:
        return full_unitout_name

"""Converts improper fractions to mixed numbers."""
# Can this be placed inside the def unit_conversion function?
def fractionalize(converted):
    # if it's in the metric dict just return it floated to 2 decimals
    # else if it's in the imperial dict, do fraction work
    if out_unit in metric_units_dict:
        return "\n%.2f" % (converted)
    else:
        whole_number = math.floor(converted)
        to_fraction  = (converted % whole_number) / 1

        if whole_number > 0:
            return "%s and %s" % (int(whole_number), Fraction(to_fraction).limit_denominator(10))
        else:
            return "%s" % Fraction(to_fraction).limit_denominator(10)


"""Prints the solution to the screen for the user."""
print "\n%s %s\n" % (fractionalize(converted), pluralize_unit())