I am getting a Type Error in this Line
You must be getting a type error because the elements of text_features and/or author_signatures are not able to be subtracted in the part i - j.

Depending on what they are, you could try converting them. For example, you could try making one or both of them numbers or strings like this:

Diff = [float(i) - float(j) for i,j in zip(text_features, author_signature)]   # both made into numbers

Diff = [str(i) - str(j) for i,j in zip(text_features, author_signature)]   # both made into strings (words)


To give better advice, you need to give an example of what your two lists are that are in the zip()

EDIT

Based on the update in the question, I see that it works as expected for me:

In [1]: text_features = [1, 2, 3]                                                         

In [2]: author_signature = [3, 2, 1]                                                      

In [3]: Diff = [i - j for i,j in zip(text_features, author_signature)]                    

In [4]: Diff                                                                              
Out[4]: [-2, 0, 2]