[Tutor] Custom Function that Takes argument

[Nym City]

Hello,
I am learning how to create custom functions and watched the tutorial online that uses API for locu to do cool stuff. I wanted to go little bit beyond the tutorial and add my own features. The problem that I am running into is that I cannot figure out how to prompt a user to input their zip code and use that information against the function. here is my code:
import urllib2
import json

locu_api = 'not included here for obvious reasons'
zip = raw_input('What is your zip: ')

def zip_search(query):
    api_key = locu_api
    url = 'https://api.locu.com/v1_0/venue/search/?api_key=' + api_key
    zip = query.replace(' ', '%20')
    final_url = url + '&zip=' + zip + "&category=restaurant"
    jason_obj = urllib2.urlopen(final_url)
    data = json.load(jason_obj)
    for item in data['objects']:
        print item['name'], item['phone'], item['street_address'], item['categories']

print zip_search(zip_search())

 Thank you.