'Returns the value associated with the given key from the given
transformer\'s data dictionary; returns default if not found.
Arguments:
transformer (BlockStructureTransformer) - The transformer
whose collected data is requested.
key (string) - A dictionary key to the transformer\'s data
that is requested.'

def get_transformer_data(self, transformer, key, default=None):

    try:
        return getattr(self.transformer_data[transformer], key, default)
    except KeyError:
        return default
