code: def test__read_pdb_raises():
      """Test private _read_pdb:
      Test if ValueError is raised for wrong file formats."""
  
      expect = (
          "Wrong file format; allowed file formats are "
          ".pdb, .pdb.gz, .ent, .ent.gz"
      )
  
      def run_code_1():
          PandasPdb()._read_pdb("protein.mol2")
  
      assert_raises(ValueError, expect, run_code_1)
  
      def run_code_2():
          PandasPdb()._read_pdb("protein.mol2.gz")
  
      assert_raises(ValueError, expect, run_code_2)
  
file_path: biopandas/biopandas/pdb/tests/test_read_pdb.py
imports: import os
  from urllib.error import HTTPError, URLError
  from urllib.request import urlopen
  import numpy
  import pandas
  from biopandas.pdb import PandasPdb
  from biopandas.testutils import assert_raises
  from nose.tools import raises
label_desc: Use image node_id 2 for calling a global function with example usage: test__read_pdb_raises() without return types