'This method corrects the components data to the right signature
(covariant/contravariant) using the metric associated with each
``TensorIndexType``.'

def data_from_tensor(self, tensor):

    tensorhead = tensor.component
    if (tensorhead.data is None):
        return None
    return self._correct_signature_from_indices(tensorhead.data, tensor.get_indices(), tensor.free, tensor.dum)
