Hey everyone:

So, I have the following function:
(2t^3+1)/((t^2+t+1)^2(t-1)^2)

I want to take get the Laurent series expansion of it. It can be seen 
through Wolfram Alpha here:
http://www.wolframalpha.com/input/?i=laurent+series+expansion+of+%282t^3%2B1%29%2F%28%28t^2%2Bt%2B1%29^2%28t-1%29^2%29

>From my understanding, it's just the taylor series expansion at t = 1. I 
try using the laurent_series function on sage as follows:

k.<t> = QQ[[]]
f = (2t^3+1)/((t^2+t+1)^2(t-1)^2)
g = f.laurent_series(); g


What I get as an output is this:

1 + 4*t^3 + 7*t^6 + 10*t^9 + 13*t^12 + 16*t^15 + 19*t^18 + O(t^20)

This isn't the Laurent Series, this is just the taylor series at t=0. 
Similarly, even in the example in the Sage docs, the laurent series of the 
power series in the example 
simply outputs the power series it started with.

sage: k.<w> = QQ[[]]
sage: f = 1+17*w+15*w^3+O(w^5)
sage: parent(f)
Power Series Ring in w over Rational Field
sage: g = f.laurent_series(); g
1 + 17*w + 15*w^3 + O(w^5)


Now, I know I can get the output I want by asking for the taylor series 
expansion about the point 1, however I was wondering why this function 
wasn't working. Or, am I not understanding this correctly. Thank you!

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