docs: def clear(self):
          """ Clear a breakpoint by removing it from all lists.
          """
          del IKBreakpoint.breakpoints_by_file_and_line[self.file_name, self.line_number]
          IKBreakpoint.breakpoints_by_number[self.number] = None
          IKBreakpoint.breakpoints_files[self.file_name].remove(self.line_number)
          if len(IKBreakpoint.breakpoints_files[self.file_name]) == 0:
              del IKBreakpoint.breakpoints_files[self.file_name]
          IKBreakpoint.update_active_breakpoint_flag()