code: def create_data():
      np_array = np.array(
          [
              ["a", "b", "c"],
              ["c", "b", "d"],
              ["d", "e", "f"],
              ["f", "e", "c"],
              ["a", "e", "d"],
              ["a", "b", "d"],
          ]
      )
      df = pd.DataFrame(np_array)
      df.to_csv("test.csv", index=False, header=False, sep="\t")
      df.to_csv("test.txt", index=False, header=False, sep="\t")
      df.to_csv(
          "test.gz",
          index=False,
          header=False,
          sep="\t",
          compression="gzip",
      )
      return np_array, len(df)
  
file_path: AmpliGraph/tests/ampligraph/datasets/test_source_identifier.py
imports: import numpy
  import pytest
  import pandas
  from ampligraph.datasets import load_csv, chunks
  from ampligraph.datasets.source_identifier import DataSourceIdentifier
  import os
label_desc: Use image node_id 1 for calling a global function with example usage: create_data() and returns: np_array,  len