Traceback (most recent call last):


 "/home/test/orm/test_transaction.py", line 692, in test_failed_rollback_deactivates_transaction_ctx_integration

evented_exceptions[0], testing.db.dialect.dbapi.IntegrityError


 "/home/test/../lib/sqlalchemy/testing/assertions.py", line 218, in is_true

is_(a, True, msg=msg)


 "/home/test/../lib/sqlalchemy/testing/assertions.py", line 227, in is_

assert a is b, msg or "%r is not %r" % (a, b)
AssertionError: False is not True

Traceback (most recent call last):


 "crf_combined_model.py", line 82, in main

model.fit(X, y)


 "/Users/max/miniconda3/envs/ma/lib/python3.6/site-packages/keras/engine/training.py", line 1013, in fit

self._make_train_function()


 "/Users/max/miniconda3/envs/ma/lib/python3.6/site-packages/keras/engine/training.py", line 497, in _make_train_function

loss=self.total_loss)


 "/Users/max/miniconda3/envs/ma/lib/python3.6/site-packages/keras/legacy/interfaces.py", line 91, in wrapper

return func(*args, **kwargs)


 "/Users/max/miniconda3/envs/ma/lib/python3.6/site-packages/keras/optimizers.py", line 445, in get_updates

grads = self.get_gradients(loss, params)


 "/Users/max/miniconda3/envs/ma/lib/python3.6/site-packages/keras/optimizers.py", line 80, in get_gradients

raise ValueError('An operation has `None` for gradient. '
ValueError: An operation has `None` for gradient. Please make sure that all of your ops have a gradient defined (i.e. are differentiable). Common ops without gradient: K.argmax, K.round, K.eval.
