code: def _set_cell_attr(self, selection, table, attr):
          
  
          # Mark content as changed
          post_command_event(self.main_window, self.ContentChangedMsg)
  
          if selection is not None:
              self.code_array.cell_attributes.append((selection, table, attr))
docs: Sets cell attr for key cell and mark grid content as changed
  
          Parameters
          ----------
  
          attr: dict
          \tContains cell attribute keys
          \tkeys in ["borderwidth_bottom", "borderwidth_right",
          \t"bordercolor_bottom", "bordercolor_right",
          \t"bgcolor", "textfont",
          \t"pointsize", "fontweight", "fontstyle", "textcolor", "underline",
          \t"strikethrough", "angle", "column-width", "row-height",
          \t"vertical_align", "justification", "frozen", "merge_area"]