func (source *source) addBaseProfiles(flagBase, flagDiffBase []*string) error {
	base, diffBase := dropEmpty(flagBase), dropEmpty(flagDiffBase)
	if len(base) > 0 && len(diffBase) > 0 {
		return errors.New("-base and -diff_base flags cannot both be specified")
	}

	source.Base = base
	if len(diffBase) > 0 {
		source.Base, source.DiffBase = diffBase, true
	}
	return nil
}

			source: s,
		})
	}

	p, pbase, m, mbase, save, err := grabSourcesAndBases(sources, bases, o.Fetch, o.Obj, o.UI, o.HTTPTransport)
	if err != nil {
		return nil, err
	}

	if pbase != nil {
		if s.DiffBase {
			pbase.SetLabel("pprof::base", []string{"true"})
		}
		if s.Normalize {
			err := p.Normalize(pbase)
			if err != nil {
				return nil, err
			}
		}
		pbase.Scale(-1)