input: Write a function to select all rows from a table where the 'status' is 'approved'. The function should execute an SQL query and return all matching rows.
  assert select_approved_rows()== [("Alice", "approved"), ("Bob", "approved")]
  assert select_approved_rows()== [("Charlie", "approved")]
  assert select_approved_rows()== []
  assert select_approved_rows()== [("Dave", "approved"), ("Eve", "approved"), ("Frank", "approved")]
output: def select_approved_rows():
      conn = sqlite3.connect('example.db')
      cursor = conn.cursor()
      cursor.execute("SELECT * FROM table_name WHERE status = 'approved'")
      rows = cursor.fetchall()
      conn.close()
      return rows