title: postgres cursor unresolved reference in python
body: <p>I wish to check if a record exists and then if it does i want to read the records in the other table. I am using the same cursor of the database that i created but it shows unresolved reference for the cursor inside the if block.
  My code:</p>
  
  <pre><code>import psycopg2
  
  conn=psycopg2.connect(host='localhost', database='my_first_db', user='postgres', password='postgres')
  curr= conn.cursor()
  res=curr.execute("select EXISTS(select * from teachers where t_name='xoxo' AND pass='xoxo2020')")
  if curr.fetchone()[0]==1 :
      {
          curr.execute("select * from students")
          result=curr.fetchall()
          for x in result:
              print(x)
          #print('Table exists')
      }
  else:
      print("not found")
  print(res)
  curr.close()
  conn.close()
  </code></pre>
  
  <p>the curr in the second line of if block shows the unresolved error.
  Thanks.</p>