docs: def BuildTemplate(self,
                      context=None,
                      output=None,
                      fleetspeak_service_config=None):
      """Find template builder and call it."""
      context = context or []
      context.append("Arch:%s" % self.GetArch())
      # Platform context has common platform settings, Target has template build
      # specific stuff.
      self.platform = platform.system()
      context.append("Platform:%s" % self.platform)
      context.append("Target:%s" % self.platform)
      if "Target:Linux" in context:
        context.append(self.GetPackageFormat())
  
      template_path = None
      if output:
        template_path = os.path.join(
            output,
            grr_config.CONFIG.Get(
                "PyInstaller.template_filename", context=context))
  
      builder_obj = self.GetBuilder(context, fleetspeak_service_config)
      builder_obj.MakeExecutableTemplate(output_file=template_path)