code: def test_load_sdf_files(self):
      current_dir = os.path.dirname(os.path.realpath(__file__))
      file_path = [
          os.path.join(current_dir, "assets", "gdb9_small.sdf")
      ]
      for df in load_sdf_files(file_path):
          break
      df_shape = (2, 6)
      self.assertEqual(df.shape, df_shape)
      self.assertEqual(df["smiles"][0], "[H]C([H])([H])[H]")
      n_atoms_mol1 = 5
      self.assertEqual(df["mol"][0].GetNumAtoms(), n_atoms_mol1)
      self.assertEqual(len(eval(df["pos_x"][0])), n_atoms_mol1)
      self.assertEqual(len(eval(df["pos_y"][0])), n_atoms_mol1)
      self.assertEqual(len(eval(df["pos_y"][0])), n_atoms_mol1)
  
imports: import unittest
  import os
  from deepchem.utils.data_utils import load_sdf_files
label_desc: Use image node_id 1 for calling the TestFileLoading obj's underlying member method code with example usage: obj.test_load_sdf_files() without return types