code: def set_default_loader(loader):
      
      if isinstance(loader, basestring):
          loader = registry.find(loader)()
      if not isinstance(loader, BaseLoader):
          loader = loader()
      global _loader
      _loader = loader
docs: Set defaulr loader instance
  
      Parameters
      ----------
      loader : instance or string
          An instance or registered name of loader class.
          The specified loader instance will be used when user did not specified
          :attr:`loader` in :func:`maidenhair.functions.load` function.
  
      See also
      --------
      :func:`maidenhair.utils.plugins.Registry.register` : Register new class