The Grerory-Leibnitz series¹ approximates $\pi$ using the alternate series

Assignment

Write a function gregory_leibnitz that takes an integer $n\in {\mathbb{N}}_0$ (int). The function must return the approximation for $\pi$ obtained from the first $n$ terms in the Grerory-Leibnitz series.

Example

                
            >>> gregory_leibnitz(1)
4.0
>>> gregory_leibnitz(10)
3.0418396189294032
>>> gregory_leibnitz(100)
3.1315929035585537
>>> gregory_leibnitz(1000)
3.140592653839794