code: def test_has_base_exceptions(self):
      excs = []
      for n in dir(psycopg2):
          obj = getattr(psycopg2, n)
          if isinstance(obj, type) and issubclass(obj, Exception):
              excs.append(obj)
  
      self.assert_(len(excs) > 8, str(excs))
  
      excs.append(psycopg2.extensions.QueryCanceledError)
      excs.append(psycopg2.extensions.TransactionRollbackError)
  
      for exc in excs:
          self.assert_(hasattr(errors, exc.__name__))
          self.assert_(getattr(errors, exc.__name__) is exc)
  
file_path: psycopg2/tests/test_errors.py
imports: import unittest
  from .testutils import ConnectingTestCase
  import psycopg2
  from psycopg2 import errors
  from psycopg2._psycopg import sqlstate_errors
  from psycopg2.errors import UndefinedTable
label_desc: Use image node_id 5 for calling the ErrorsTests obj's underlying member method code with example usage: obj.test_has_base_exceptions() without return types