class_docstr: Rating Metric.
  
  Attributes
  ----------
  name: string,
      Name of the measure.
  
  type: string, value: 'rating'
      Type of the metric, e.g., "ranking", "rating".
code: def compute(self, **kwargs):
      raise NotImplementedError()
  
file_path: cornac/cornac/metrics/rating.py
imports: import numpy
label_desc: Use image node_id 2 for calling the RatingMetric obj's underlying member method code with example usage: obj.compute() without return types