code: def _build_rules(specs):
      
      for spec in specs:
          if "context" in spec:
              yield Context(spec["context"], list(_build_rules(spec.get("routes", []))))
          else:
              rulespec = spec.copy()
              match = rulespec.pop("match")
              name = rulespec.pop("name")
              yield Rule(match, endpoint=name, **rulespec)
docs: Adapts the list of anillo urlmapping specs into
      a list of werkzeug rules or rules subclasses.
  
      :param list specs: A list of anillo url mapping specs.
      :return: generator