Identify the predecessors of a player for a given permutation

To find the predecessors \(S_{\pi}(i)\) of a player \(i\) for a permutation \(\pi\) use coopgt.shapley_value.predecessors.

For example to find \(S_{(3, 2, 1)}(1)\):

>>> import coopgt.shapley_value
>>> pi = (3, 2, 1)
>>> coopgt.shapley_value.predecessors(permutation=pi, i=1)
{2, 3}