
def  mapNameToLastNames(data):
    namemap = {}
    for [first,last] in data:
        if first not in namemap:
            namemap[first] = [last]
        else:
            namemap[first].append(last)
    return namemap

namelist = [['Susan', 'Smith'], ['Jackie', 'Long'], ['Mary', 'White'], ['Susan', 'Brandt'], ['Jackie', 'Johnson'], ['Susan', 'Rodger']]
print "namelist is: ", namelist 
print

namemap = mapNameToLastNames(namelist)
print namemap

     