code: def test_fetch_after_async(self):
      cur = self.conn.cursor()
      cur.execute("select 'a'")
  
      # a fetch after an asynchronous query should raise an error
      self.assertRaises(psycopg2.ProgrammingError, cur.fetchall)
      # but after waiting it should work
      self.wait(cur)
      self.assertEquals(cur.fetchall()[0][0], "a")
  
imports: import gc
  import time
  import unittest
  import warnings
  import psycopg2
  import psycopg2.errors
  from psycopg2 import extensions
  from .testutils import ConnectingTestCase, StringIO, skip_before_postgres, skip_if_crdb, crdb_version, slow
label_desc: Use image node_id 7 for calling the AsyncTests obj's underlying member method code with example usage: obj.test_fetch_after_async() without return types