'Updates the given transformer\'s data dictionary with the given
key and value.
Arguments:
transformer (BlockStructureTransformer) - The transformer
whose data is to be updated.
key (string) - A dictionary key to the transformer\'s data.
value (any picklable type) - The value to associate with the
given key for the given transformer\'s data.'

def set_transformer_data(self, transformer, key, value):

    setattr(self.transformer_data.get_or_create(transformer), key, value)
