Function _case_helper

Implementation of case that allows for different cond functions. Args: cond_fn: method that has signature and semantics of `cond` above. pred_fn_pairs: Dict or list of pairs of a boolean scalar tensor, and a callable which returns a list of tensors. default: Optional callable th

(cond_fn,
                 pred_fn_pairs,
                 default,
                 exclusive,
                 name,
                 allow_python_preds=False,
                 **cond_kwargs)