What method was used here to expand $\ln(z)$? On Wikipedia's entry for bilinear transform, there is this formula:
\begin{align}
s &= \frac{1}{T} \ln(z) \\[6pt]
  &= \frac{2}{T} \left[\frac{z-1}{z+1} + \frac{1}{3} \left( \frac{z-1}{z+1} \right)^3  + \frac{1}{5} \left( \frac{z-1}{z+1} \right)^5  + \frac{1}{7} \left( \frac{z-1}{z+1} \right)^7 + \cdots \right] \\[6pt]
  &\approx  \frac{2}{T} \frac{z - 1}{z + 1} \\[6pt]
  &=  \frac{2}{T} \frac{1 - z^{-1}}{1 + z^{-1}}
\end{align}
What is the method that is used to expand $\ln(z)$? Taylor series? Laurent series? Some other techniques?

$$
z = \frac{1+\frac{z-1}{z+1}}{1-\frac{z-1}{z+1}}
$$
