code: def create_collection(href, cls):
      
      instance = cls(href=href)
      meth = getattr(instance, 'create')
      return type(
           cls.__name__, (SubElementCollection,), {'create': meth})(href, cls)
docs: This collection type inserts a ``create`` method into the collection.
      This will proxy to the sub elements create method while restricting
      access to other attributes that wouldn't be initialized yet.
      
      .. py:method:: create(...)
      
      Create method is inserted dynamically for the collection class type.
      See the class types documentation, or use help().
  
      :rtype: SubElementCollection