I'm interested in how would one find Taylor series of a function
$$f(z)=\left(1-\frac1z \right)^3$$ around $z_0=2$.
I have no clue where to start, the $3$ in the exponent baffles me. I tried to use the cube of the sum formula, but to no avail. I tried to find the series of a function $f(z)=1-1/z$ but I'm not sure where to go from there.
Any help would be appreciated.