code: def _compute_linf_contributions_histogram(
      col, backend: pipeline_backend.PipelineBackend
  ):
      """Computes histogram of per partition privacy id contributions.
  
      This histogram contains: the number of (privacy id, partition_key)-pairs
      which have 1 row in the datasets, 2 rows etc.
  
      Args:
          col: collection with elements (privacy_id, partition_key).
          backend: PipelineBackend to run operations on the collection.
      Returns:
          1 element collection, which contains the computed hist.Histogram.
      """
      col = backend.count_per_element(
          col, "Contributions per (privacy_id, partition)"
      )
      # col: ((pid, pk), n)
  
      col = backend.values(col, "Drop privacy id")
      # col: (int)
  
      return _compute_frequency_histogram(
          col, backend, hist.HistogramType.LINF_CONTRIBUTIONS
      )
  
imports: import bisect
  import operator
  from typing import List, Tuple
  import numpy
  import pipeline_dp
  from pipeline_dp import pipeline_backend, pipeline_functions
  from pipeline_dp.dataset_histograms import histograms
label_desc: Use image node_id 12 for calling a global function with example usage: _compute_linf_contributions_histogram(col, backend) and returns: _compute_frequency_histogram