code: def create_runtime(self,
                         env,            # type: MutableMapping[Text, Text]
                         runtime_context  # type: RuntimeContext
                        ):  # type: (...) -> Tuple[List, Optional[Text]]
          
          any_path_okay = self.builder.get_requirement("DockerRequirement")[1] \
              or False
          runtime = [u"singularity", u"--quiet", u"exec", u"--contain", u"--pid",
                     u"--ipc"]
          if _singularity_supports_userns():
              runtime.append(u"--userns")
          runtime.append(u"--bind")
          runtime.append(u"{}:{}:rw".format(
              docker_windows_path_adjust(os.path.realpath(self.outdir)),
              self.builder.outdir))
          runtime.append(u"--bind")
          tmpdir = "/tmp"  # nosec
          runtime.append(u"{}:{}:rw".format(
              docker_windows_path_adjust(os.path.realpath(self.tmpdir)), tmpdir))
  
          self.add_volumes(self.pathmapper, runtime, any_path_okay=True,
                           secret_store=runtime_context.secret_store,
                           tmpdir_prefix=runtime_context.tmpdir_prefix)
          if self.generatemapper is not None:
              self.add_volumes(
                  self.generatemapper, runtime, any_path_okay=any_path_okay,
                  secret_store=runtime_context.secret_store,
                  tmpdir_prefix=runtime_context.tmpdir_prefix)
  
          runtime.append(u"--pwd")
          runtime.append(u"%s" % (docker_windows_path_adjust(self.builder.outdir)))
  
          if runtime_context.custom_net:
              raise UnsupportedRequirement(
                  "Singularity implementation does not support custom networking")
          elif runtime_context.disable_net:
              runtime.append(u"--net")
  
          env["SINGULARITYENV_TMPDIR"] = tmpdir
          env["SINGULARITYENV_HOME"] = self.builder.outdir
  
          for name, value in self.environment.items():
              env["SINGULARITYENV_{}".format(name)] = str(value)
          return (runtime, None)
docs: Returns the Singularity runtime list of commands and options.