int or None. The axis to picking the elements. Negative values means indexing from right to left. If is
None, the elements in the index w.r.t the flattened input will be picked.
If true, the axis where we pick the elements is left in the result as dimension with size one.
Specify how out-of-bound indices behave. Default is "clip". "clip" means clip to the range. So, if all indices mentioned are too large, they are replaced by the index that addresses the last element along an axis. "wrap" means to wrap around.