l050ZZ1bAsBddd7hE1GD => {'wordcount': {'page3': 130, 'page2': 120, 'page1': 100}, 'availability_date': DatetimeWithNanoseconds(2019, 3, 4, 6, 0, tzinfo=<UTC>), 'count': 100}
JCn6BxwfEDIvirnkMyOf => {'wordcount': {'page3': 180, 'page2': 120, 'page1': 150}, 'availability_date': DatetimeWithNanoseconds(2019, 3, 4, 6, 0, tzinfo=<UTC>), 'count': 150}
nfW0ybNz4WPGWtikfVK2 => {'count': 200, 'wordcount': {'page3': 50, 'page2': 100, 'page1': 200}}
last value: 200
Traceback (most recent call last):
  File "/home/ctorres/.local/lib/python3.5/site-packages/google/cloud/firestore_v1/query.py", line 642, in _normalize_cursor
    values.append(field_path_module.get_nested_value(order_key, data))
  File "/home/ctorres/.local/lib/python3.5/site-packages/google/cloud/firestore_v1/field_path.py", line 243, in get_nested_value
    raise KeyError(msg)
KeyError: "'wordcount' is not contained in the data"

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "firestore_pagination.py", line 28, in <module>
    docs_list = list(docs)
  File "/home/ctorres/.local/lib/python3.5/site-packages/google/cloud/firestore_v1/query.py", line 736, in stream
    self._to_protobuf(),
  File "/home/ctorres/.local/lib/python3.5/site-packages/google/cloud/firestore_v1/query.py", line 675, in _to_protobuf
    start_at = self._normalize_cursor(self._start_at, orders)
  File "/home/ctorres/.local/lib/python3.5/site-packages/google/cloud/firestore_v1/query.py", line 645, in _normalize_cursor
    raise ValueError(msg)
ValueError: The "order by" field path 'wordcount.page1' is not present in the cursor data {'wordcount.page1': 200}. All fields sent to ``order_by()`` must be present in the fields if passed to one of ``start_at()`` / ``start_after()`` / ``end_before()`` / ``end_at()`` to define a cursor.