docs: def export_dist(self, args):
          """Copies a created dist to an output dir.
  
          This makes it easy to navigate to the dist to investigate it
          or call build.py, though you do not in general need to do this
          and can use the apk command instead.
          """
          ctx = self.ctx
          dist = dist_from_args(ctx, args)
          if dist.needs_build:
              raise BuildInterruptingException(
                  'You asked to export a dist, but there is no dist '
                  'with suitable recipes available. For now, you must '
                  ' create one first with the create argument.')
          if args.symlink:
              shprint(sh.ln, '-s', dist.dist_dir, args.output_dir)
          else:
              shprint(sh.cp, '-r', dist.dist_dir, args.output_dir)