input: Write a python function to check if a given database exists in the MySQL server.
  assert check_database_exists("new_database")==True
  assert check_database_exists("non_existent_database")==False
output: def check_database_exists(database_name):
      import mysql.connector
      from mysql.connector import errorcode
  
      try:
          cnx = mysql.connector.connect(user='your_user', password='your_password', host='your_host')
          cursor = cnx.cursor()
          cursor.execute("SHOW DATABASES LIKE %s", (database_name,))
          result = cursor.fetchone()
          cursor.close()
          cnx.close()
          return result is not None
      except mysql.connector.Error as err:
          if err.errno == errorcode.ER_ACCESS_DENIED_ERROR:
              print("Something is wrong with your user name or password")
          elif err.errno == errorcode.ER_BAD_DB_ERROR:
              print("Database does not exist")
          else:
              print(err)
          return False