input: Write a function to select all rows from a table where the 'status' is 'approved'. The function should execute the SQL query and return all matching rows.
  assert select_approved_rows() == [(1, 'John', 'approved'), (2, 'Jane', '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