code: def test_sparse_bin_centers_x():
      hist1, hist2, hist3 = get_histograms()
  
      centers3, values3 = sparse_bin_centers_x(hist3)
  
      np.testing.assert_array_equal(
          centers3,
          [
              1.2308112e18,
              1.2308976e18,
              1.2311568e18,
              1.2312432e18,
              1.2313296e18,
          ],
      )
  
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 6 for calling a global function with example usage: test_sparse_bin_centers_x() without return types