ValueError: Failed to convert a NumPy array to a Tensor (Unsupported object type numpy.ndarray). To use for embeddings

Question

I have the following Keras data generator, that receives pairs as input of the form:

    pairs = [((0, 1, 2), 0), 
             ((3, 4, 5, 6, 7, 8, 9, 10, 11), 0)