text: """
  Wrapper class that takes a list of template loaders as an argument and attempts
  to load templates from them in order, caching the result.
  """
  
  import hashlib
  
  from django.template import TemplateDoesNotExist
  from django.template.backends.django import copy_exception
  
  from .base import Loader as BaseLoader
  
  
  class Loader(BaseLoader):
  
      def __init__(self, engine, loaders):
          self.get_template_cache = {}
          self.loaders = engine.get_template_loaders(loaders)
          super().__init__(engine)
  
      def get_contents(self, origin):
          return origin.loader.get_contents(origin)
  
      def get_template(self, template_name, skip=None):
          """
          Perform the caching that gives this loader its name. Often many of the
          templates attempted will be missing, so memory use is of concern here.
          To keep it in check, caching behavior is a little complicated when a
          template is not found. See ticket #26306 for more details.
  
          With template debugging disabled, cache the TemplateDoesNotExist class
          for every missing template and raise a new instance of it after
          fetching it from the cache.
  
          With template debugging enabled, a unique TemplateDoesNotExist object
          is cached for each missing template to preserve debug data. When
          raising an exception, Python sets __traceback__, __context__, and
          __cause__ attributes on it. Those attributes can contain references to
          all sorts of objects up the call chain and caching them creates a
          memory leak. Thus, unraised copies of the exceptions are cached and
          copies of those copies are raised after they're fetched from the cache.
          """
          key = self.cache_key(template_name, skip)
          cached = self.get_template_cache.get(key)
          if cached:
              if isinstance(cached, type) and issubclass(cached, TemplateDoesNotExist):
                  raise cached(template_name)
              elif isinstance(cached, TemplateDoesNotExist):
                  raise copy_exception(cached)
              return cached
  
          try:
              template = super().get_template(template_name, skip)
          except TemplateDoesNotExist as e:
              self.get_template_cache[key] = copy_exception(e) if self.engine.debug else TemplateDoesNotExist
              raise
          else:
              self.get_template_cache[key] = template
  
          return template
  
      def get_template_sources(self, template_name):
          for loader in self.loaders:
              yield from loader.get_template_sources(template_name)
  
      def cache_key(self, template_name, skip=None):
          """
          Generate a cache key for the template name and skip.
  
          If skip is provided, only origins that match template_name are included
          in the cache key. This ensures each template is only parsed and cached
          once if contained in different extend chains like:
  
              x -> a -> a
              y -> a -> a
              z -> a -> a
          """
          skip_prefix = ''
  
          if skip:
              matching = [origin.name for origin in skip if origin.template_name == template_name]
              if matching:
                  skip_prefix = self.generate_hash(matching)
  
          return '-'.join(s for s in (str(template_name), skip_prefix) if s)
  
      def generate_hash(self, values):
          return hashlib.sha1('|'.join(values).encode()).hexdigest()
  
      def reset(self):
          "Empty the template cache."
          self.get_template_cache.clear()
  