Traceback (most recent call last):


 "<string>", line 1, in <module>


 "/usr/local/lib/python3.5/dist-packages/dateutil/parser/_parser.py", line 1356, in parse

return DEFAULTPARSER.parse(timestr, **kwargs)


 "/usr/local/lib/python3.5/dist-packages/dateutil/parser/_parser.py", line 648, in parse

raise ValueError("Unknown string format:", timestr)
ValueError: ('Unknown string format:', '2018-12-10 17:55:02 (GMT+0:00)')

Traceback (most recent call last):


 "run_tf_ner.py", line 299, in <module>

main()


 "run_tf_ner.py", line 231, in main

trainer.train()


 "/.conda/envs/xftf2/lib/python3.6/site-packages/transformers/trainer_tf.py", line 457, in train

train_ds = self.get_train_tfdataset()


 "/.conda/envs/xftf2/lib/python3.6/site-packages/transformers/trainer_tf.py", line 141, in get_train_tfdataset

raise ValueError("The training dataset must have an asserted cardinality")
ValueError: The training dataset must have an asserted cardinality
