docs: def set_slimits_for_all(self, row_column_list=None, min=None, max=None):
          """Set point size limits of specified subplots.
  
          :param row_column_list: a list containing (row, column) tuples to
              specify the subplots, or None to indicate *all* subplots.
          :type row_column_list: list or None
          :param min: point size for the lowest value.
          :param max: point size for the highest value.
  
          """
          if min is None or max is None:
              raise Exception('Both min and max are required.')
          if row_column_list is None:
              self.limits['smin'] = sqrt(min)
              self.limits['smax'] = sqrt(max)
          else:
              for row, column in row_column_list:
                  self.set_slimits(row, column, min, max)