code: def test_len():
      """Test that len(dataset) works."""
      solubility_dataset = load_solubility_data()
      assert len(solubility_dataset) == 10
  
imports: import random
  import math
  import unittest
  import os
  import numpy
  import pytest
  import deepchem
  import pandas
  import tempfile
label_desc: Use image node_id 9 for calling a global function with example usage: test_len() without return types