wordbook | DICT Python Client | Build Tool library

im trying to make a function that takes two files, say x and y, and returns a xls book, the function would create a number of sheets with the names selected from the x file, x would look like this

I'm programming a little programm in C wich should count unique words in c. To do this, i'm having an wordbook to store all found words. Normaly it should only put words inside that aren't already in it but it keeps entering all writen words. How can i fix this and how can i delete all the empty parts in my wordbook "woerterbuch" ?