code: def column_widths(self, size, focus=False):
          
          maxcol = size[0]
          self._cache_maxcol = maxcol
          widths = [width for i, (w, (t, width, b)) in enumerate(self.contents)]
          self._cache_column_widths = widths
  
          return widths
docs: Return a list of column widths.
  
          0 values in the list mean hide corresponding column completely