Add missing dictionary key/value via raw_input

Question

import collections
header_dict = {'account number':'ACCOUNT_name','accountID':'ACCOUNT_name','name':'client','first name':'client','tax id':'tin'}
#header_dict = collections.defaultdict(lambda: 'tin') # attempted use of defaultdict...destroys my dictionary
given_header = ['account number','name','tax id']#,'tax identification number']#,'social security number'
#given_header = ['account number','name','tax identification number']...non working header layout
fileLayout = [header_dict[ting] for ting in given_header if ting] #create if else..if ting exists, add to list...else if not in list, add to dictionary

def getLayout(ting):
    global given_header
    global fileLayout
    return given_header[fileLayout.index(ting)]

print getLayout('ACCOUNT_name')
print getLayout('client')
print getLayout('tin')
rows = zip((getLayout('ACCOUNT_name'),getLayout('client'),getLayout('tin')))
print rows

I am working with many files of random, mixed up layouts/column orders. I have a set template for my db table of 'ACCOUNT_name','client','tin' that I want the files to be ordered in. I have created a dictionary of the possible header/column names I might find in other files as keys and my set header names as values. So, for example, if I wanted to see where to put the column 'account number' from one of my given files, I would type header_dict['account number']. This would give me the corresponding column from my template, 'ACCOUNT_name'. This works great...I also added another feature. Instead of having to type 'account number'..I made a list comprehension that looks up each value by key.

This list I just created with the 'fileLayout' list comprehension essentially transforms my given file's header into my desired names: ['ACCOUNT_name','client'] That makes life a lot easier...I know that I want to look up 'ACCOUNT_name', or 'client'. Next I run a function 'getLayout' that returns the index of the desired columns I am searching...So if I want to see where my desired column 'ACCOUNT_name' is in the file, I just run the function which is called like this...

getLayout('ACCOUNT_name')  

Now at this point, I can easily print the columns to my order...with:

rows = zip((getLayout('ACCOUNT_name'),getLayout('client'),getLayout('tin')))
print rows

The above code gives me [('account number'),('name'),('tax id')], which is exactly what I want...

But what if there is a new header I am not used to ?? Lets use the same example code above but change the list 'given_header' to this:

given_header = ['account number','name','tax identification number']

I most certainly get the key error, KeyError: 'tax identification number' I know I can use defaultdict but when I try to use it with the set value 'tin', I end up overwriting my entire dictionary... What I would ultimately like to end up doing is this...

I would like to create an else within my list comprehension that allows me to standard input dictionary entries if they don't exist. In other words, since 'tax identification number' does not exists as a key, add it as one to my dict and give it the value 'tin' via raw_input. Has anyone ever done or tried anything like this? Any ideas? If you have and have any suggestions, I am all ears. I'm struggling on this issue...

The way I would want to go about this is in the list comprehension..

fileLayout = [header_dict[ting] for ting in given_header if ting else raw_input('add missing key value pair to dictionary')] # or do something of the sort.