code: def select(cls, dataset, selection_mask=None, **selection):
          
          selection = {k: slice(*sel) if isinstance(sel, tuple) else sel
                       for k, sel in selection.items()}
          coords = tuple(selection[kd.name] if kd.name in selection else slice(None)
                         for kd in dataset.kdims)
          if not any([isinstance(el, slice) for el in coords]):
              return dataset.data[dataset.sheet2matrixidx(*coords)]
  
          # Apply slices
          xidx, yidx = coords
          l, b, r, t = dataset.bounds.lbrt()
          if isinstance(xidx, slice):
              l = l if xidx.start is None else max(l, xidx.start)
              r = r if xidx.stop is None else min(r, xidx.stop)
          if isinstance(yidx, slice):
              b = b if yidx.start is None else max(b, yidx.start)
              t = t if yidx.stop is None else min(t, yidx.stop)
          bounds = BoundingBox(points=((l, b), (r, t)))
          slc = Slice(bounds, dataset)
          return slc.submatrix(dataset.data)
docs: Slice the underlying numpy array in sheet coordinates.