Print a summary of the model. The summary includes a description of training data, options, hyper-parameters, and statistics measured during model creation.
- output : str, None
The type of summary to return.
- None or ‘stdout’ : print directly to stdout.
- ‘str’ : string of summary
- ‘dict’ : a dict with ‘sections’ and ‘section_titles’ ordered lists. The entries in the ‘sections’ list are tuples of the form (‘label’, ‘value’).