a currency converter that uses the yahoo finance API to find exchange rates

currency_converter.py

import urllib2
import json
def currencyConverter(from_value,target_value,currency_quantity):
    yahoo_exchange_url = "https://query.yahooapis.com/v1/public/yql"
    yahoo_query = 'select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20("'+currency_from+currency_to+'")'
    yql_query_url = yql_base_url + "?q=" + yql_query + "&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys"
    try:
        yql_response = urllib2.urlopen(yql_query_url)
        try:
            yql_json = json.loads(yql_response.read())
            currency_output = currency_input * float(yql_json['query']['results']['rate']['Rate'])
            return currency_output
        except (ValueError, KeyError, TypeError):
            return "JSON format error"
    
    except IOError, e:
        if hasattr(e, 'code'):
            return e.code
        elif hasattr(e, 'reason'):
            return e.reason


currency_quantity = int(raw_input("How much currency should be converted?: "))
from_value = str(raw_input("What is the currency that needs to be converted?: "))
target_value = str(raw_input("Please enter currency to convert to: "))
exchange_rate = currencyConverter(from_value,target_value,currency_quantity)
print exchange_rate