import tensorflow as tf

                        )
                    else:
                        # vector vector -> concat
                        dependencies_hidden.append(dependency_final_hidden)

            try:
                hidden = tf.concat([hidden] + dependencies_hidden, -1)
            except:
                raise ValueError(
                    'Shape mismatch while concatenating dependent features of '
                    '{}: {}. Concatenating the feature activations tensor {} '
                    'with activation tensors of dependencies: {}. The error is '
