docs: def to_resolvers(sweepable: Sweepable) -> List[ParamResolver]:
      """Convert a Sweepable to a list of ParamResolvers."""
      if isinstance(sweepable, ParamResolver):
          return [sweepable]
      elif isinstance(sweepable, Sweep):
          return list(sweepable)
      elif isinstance(sweepable, collections.Iterable):
          iterable = cast(collections.Iterable, sweepable)
          return list(iterable) if isinstance(next(iter(iterable)),
                                              ParamResolver) else sum(
              [list(s) for s in iterable], [])
      raise TypeError('Unexpected Sweepable type.')