input: Write a python function to select approved rows from a database table.
  assert select_approved_rows() == [('row1_data', 'approved'), ('row2_data', 'approved')]
  assert select_approved_rows() == [('row3_data', 'approved'), ('row4_data', 'approved')]
  assert select_approved_rows() == []
output: def select_approved_rows():
      import sqlite3
  
      # Connect to a database (or create one if it doesn't exist)
      conn = sqlite3.connect(':memory:')
      cursor = conn.cursor()
  
      # Create a sample table
      cursor.execute('''
      CREATE TABLE sample_table (
          id INTEGER PRIMARY KEY AUTOINCREMENT,
          data TEXT NOT NULL,
          status TEXT NOT NULL
      )
      ''')
  
      # Insert sample data
      cursor.executemany('''
      INSERT INTO sample_table (data, status)
      VALUES (?, ?)
      ''', [
          ('row1_data', 'approved'),
          ('row2_data', 'approved'),
          ('row3_data', 'pending'),
          ('row4_data', 'rejected'),
          ('row5_data', 'approved')
      ])
  
      # Query approved rows
      cursor.execute('''
      SELECT data, status FROM sample_table WHERE status = 'approved'
      ''')
  
      approved_rows = cursor.fetchall()
  
      # Close the connection
      conn.close()
  
      return approved_rows