class_docstr: Base class for evaluators.
class_docstr_tok: ["Base","class","for","evaluators","."]
docstr: Logs metrics.
docstr_tok: ["Logs","metrics","."]
code: def flush(self, step):
      """Logs metrics."""
      raise NotImplementedError()
  
imports: import ddsp
  from ddsp.training import heuristics
  from ddsp.training import metrics
  from ddsp.training import summaries
  import gin
  import numpy
  import tensorflow.compat.v2
label_desc: Use image node_id 5 for calling the BaseEvaluator obj's underlying member method code with example usage: obj.flush(step) without return types