code: def test_sum_entries():
      hist1, hist2, hist3 = get_histograms()
  
      assert sum_entries(hist1) == 5
      assert sum_entries(hist2) == 5
      assert sum_entries(hist3) == 5
  
file_path: popmon/tests/popmon/hist/test_histogram.py
imports: import histogrammar
  import numpy
  import pandas
  from popmon.hist.hist_utils import is_numeric, is_timestamp, project_on_x, project_split2dhist_on_axis, sparse_bin_centers_x, split_hist_along_first_dimension, sum_entries, sum_over_x
label_desc: Use image node_id 8 for calling a global function with example usage: test_sum_entries() without return types