def __init__(self, retriever):
    """Initializes an instance of an Iterator.

    Args:
      retriever: a function that can retrieve the next page of items.
    """
    self._page_token = None
    self._first_page = True
    self._retriever = retriever
    self._count = 0
def __init__ ( self , retriever ) : self . _page_token = None self . _first_page = True self . _retriever = retriever self . _count = 0
Initializes an instance of an Iterator.

    Args:
      retriever: a function that can retrieve the next page of items.