def mat_slice_of_slice(parent, rowslice, colslice):
 row = slice_of_slice(parent.rowslice, rowslice)
 col = slice_of_slice(parent.colslice, colslice)
 return MatrixSlice(parent.parent, row, col)

def mat_slice_of_slice ( parent , rowslice , colslice ) : row = slice_of_slice ( parent . rowslice , rowslice ) col = slice_of_slice ( parent . colslice , colslice ) return MatrixSlice ( parent . parent , row , col )
collapse nested matrix slices .