How to return unique words from the text file using Python

Question

How do I return all the unique words from a text file using Python? For example:

I am not a robot

I am a human

Should return:

Answer 1

try:
    with open("gridlex.txt",mode="r",encoding="utf-8")as india:

        for data in india:
            if chr(data)==chr(data):
                print("no of chrats",len(chr(data)))
            else:
                print("data")
except IOError:
    print("sorry")