code: def example_rates_to_pmf(example_rates):
      """Creates a probability-mass-function based on relative example rates.
  
      Args:
        example_rates: a list or tuple
      Returns:
        a list of floats
      """
      total = sum(example_rates)
      return [r / total for r in example_rates]
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import functools
  import os
  import numpy
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_problems
  import tensorflow.compat.v1
label_desc: Use image node_id 7 for calling a global function with example usage: example_rates_to_pmf(example_rates) and returns: unknown