docs: def parse_flux_bounds(entry):
      """Return flux bounds for reaction entry.
  
      Detect flux bounds that are specified using the non-standardized
      kinetic law parameters which are used by many pre-FBC SBML models. The
      flux bounds are returned as a pair of lower, upper bounds. The returned
      bound is None if undefined.
  
      Args:
          entry: :class:`SBMLReactionEntry`.
      """
      lower_bound = None
      upper_bound = None
      for parameter in entry.kinetic_law_reaction_parameters:
          pid, name, value, units = parameter
          if pid == 'UPPER_BOUND' or name == 'UPPER_BOUND':
              upper_bound = value
          elif pid == 'LOWER_BOUND' or name == 'LOWER_BOUND':
              lower_bound = value
  
      return lower_bound, upper_bound