Traceback (most recent call last):


 "<stdin>", line 8, in <module>


 "venv/lib/python3.7/site-packages/flair/trainers/trainer.py", line 331, in train

loss = self.model.forward_loss(batch_step)


 "venv/lib/python3.7/site-packages/flair/models/sequence_tagger_model.py", line 493, in forward_loss

features = self.forward(data_points)


 "venv/lib/python3.7/site-packages/apex/amp/_initialize.py", line 197, in new_fwd

**applier(kwargs, input_caster))


 "venv/lib/python3.7/site-packages/flair/models/sequence_tagger_model.py", line 498, in forward

self.embeddings.embed(sentences)


 "venv/lib/python3.7/site-packages/flair/embeddings.py", line 177, in embed

embedding.embed(sentences)


 "venv/lib/python3.7/site-packages/flair/embeddings.py", line 87, in embed

for token in sentence.tokens:
AttributeError: 'NoneType' object has no attribute 'tokens'

Traceback (most recent call last):


 "test.py", line 14, in <module>

loss.backward()


 "/home/delta/dev/chainer/chainer/variable.py", line 966, in backward

self._backward_main(retain_grad, loss_scale)


 "/home/delta/dev/chainer/chainer/variable.py", line 1095, in _backward_main

target_input_indexes, out_grad, in_grad)


 "/home/delta/dev/chainer/chainer/function_node.py", line 548, in backward_accumulate

gxs = self.backward(target_input_indexes, grad_outputs)


 "/home/delta/dev/chainer/chainer/functions/array/tile.py", line 50, in backward

for i in range(gy.ndim):


 "/home/delta/dev/chainer/chainer/variable.py", line 703, in ndim

return self.data.ndim
AttributeError: 'NoneType' object has no attribute 'ndim'
