code: def clear_breakpoint(self, filename, lineno):
          
          clear_breakpoint(filename, lineno)
          self.breakpoints_saved.emit()
          editorstack = self.get_current_editorstack()
          if editorstack is not None:
              index = self.is_file_opened(filename)
              if index is not None:
                  editorstack.data[index].editor.debugger.toogle_breakpoint(
                          lineno)
docs: Remove a single breakpoint