code: def get_test_histograms1():
      """Get set 1 of test histograms"""
      # dummy dataset with mixed types
      # convert timestamp (col D) to nanosec since 1970-1-1
      df = pd._testing.makeMixedDataFrame()
      df["date"] = df["D"].apply(to_ns)
      df["boolT"] = True
      df["boolF"] = False
  
      # building 1d-, 2d-, and 3d-histogram (iteratively)
      hist1 = hg.Categorize(unit("C"))
      hist2 = hg.Bin(5, 0, 5, unit("A"), value=hist1)
      hist3 = hg.SparselyBin(
          origin=pd.Timestamp("2009-01-01").value,
          binWidth=pd.Timedelta(days=1).value,
          quantity=unit("date"),
          value=hist2,
      )
      # fill them
      hist1.fill.numpy(df)
      hist2.fill.numpy(df)
      hist3.fill.numpy(df)
  
      return df, hist1, hist2, hist3
  
file_path: popmon/tests/popmon/analysis/test_hist_numpy.py
imports: import histogrammar
  import numpy
  import pandas
  import pytest
  from popmon.analysis.hist_numpy import assert_similar_hists, check_similar_hists, get_2dgrid, get_consistent_numpy_1dhists, get_consistent_numpy_2dgrids, get_consistent_numpy_entries, get_contentType, prepare_2dgrid, set_2dgrid
label_desc: Use image node_id 3 for calling a global function with example usage: get_test_histograms1() and returns: df,  hist1,  hist2,  hist3