How does the VoxelGrid.CheckIfIncluded(3DVector) works?

[TangerineVoid]

So this is the function used to identify which data points are included inside a voxel body. The output is a True/False array for each input data point.

std::vector<bool> VoxelGrid::CheckIfIncluded(
        const std::vector<Eigen::Vector3d> &queries) {
    std::vector<bool> output;
    output.resize(queries.size());
    size_t i = 0;
    for (auto &query_double : queries) {
        auto query = GetVoxel(query_double);
        output[i] = voxels_.count(query) > 0;
        i++;
    }
    return output;
}

I understand that in the for loop, for each given point, the closest voxel to the point is obtained. But what is happening in the voxels_.count(query) > 0 ?
I haven't been able to find the .count method anywhere.

Eigen::Vector3i VoxelGrid::GetVoxel(const Eigen::Vector3d &point) const {
    Eigen::Vector3d voxel_f = (point - origin_) / voxel_size_;
    return (Eigen::floor(voxel_f.array())).cast<int>();
}

It would help me a lot any inside on how this is being computed. The official documentation just says that a Element-wise operation is performed to identify which points are inside the voxels.

Documentation:

check_if_included(self, queries)
Element-wise check if a query in the list is included in the VoxelGrid. Queries are double precision and are mapped to the closest voxel.

PARAMETERS:
queries ([open3d.utility.Vector3dVector](https://www.open3d.org/docs/release/python_api/open3d.utility.Vector3dVector.html#open3d.utility.Vector3dVector)) –

RETURNS:
List[bool]

Thanks,