[cnn] random seed: 123456789
[cnn] allocating memory: 512MB
[cnn] memory allocation done.
Using external embedding: ../../cbow.vectors
Preparing vocab
Finished collecting vocab
Initializing blstm arc hybrid:
Load external embedding. Vector dimensions 50
Starting epoch 0
Traceback (most recent call last):
  File "src/parser.py", line 50, in <module>
    parser.Train(options.conll_train)
  File "/data/dutch_parser/bist_parser/barchybrid/src/arc_hybrid.py", line 311, in Train
    self.Init()
  File "/data/dutch_parser/bist_parser/barchybrid/src/arc_hybrid.py", line 183, in Init
    self.empty = paddingVec if self.nnvecs == 1 else concatenate([paddingVec for _ in xrange(self.nnvecs)])
  File "pycnn.pyx", line 718, in pycnn.concatenate (pycnn.cpp:21057)
  File "pycnn.pyx", line 719, in pycnn.concatenate (pycnn.cpp:20933)
AssertionError: List is empty, nothing to concatenate.