class_docstr: Interface for performing each step of a training algorithm.
docstr: Perform one step of this training algorithm.
docstr_tok: ["Perform","one","step","of","this","training","algorithm","."]
code: def __call__(self):
      """Perform one step of this training algorithm."""
      raise NotImplementedError("must be implemented in descendants")
  
file_path: tensorflow/tensorflow/python/distribute/step_fn.py
imports: from tensorflow.python.eager import backprop
  from tensorflow.python.training import optimizer
label_desc: Use image node_id 4 for calling the Step obj's underlying member method code with example usage: obj.__call__() without return types