input: Write a python function to fetch all records from a MySQL database using the provided connection details and print them.
  assert fetch_records() == [(1, 'John Doe', 'john@example.com'), (2, 'Jane Smith', 'jane@example.com')]
  assert fetch_records() == [(3, 'Emily Davis', 'emily@example.com'), (4, 'Michael Brown', 'michael@example.com')]
  assert fetch_records() == [(5, 'Sarah Wilson', 'sarah@example.com'), (6, 'David Lee', 'david@example.com')]
output: import mysql.connector
  
  def fetch_records():
      connection = mysql.connector.connect(
          host='localhost',
          user='username',
          password='password',
          database='testdb'
      )
      cursor = connection.cursor()
      cursor.execute("SELECT * FROM users")
      records = cursor.fetchall()
      cursor.close()
      connection.close()
      return records