<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def change_db_user_password(username, password):
 """Change a db user's password."""


    sql = "ALTER USER %s WITH PASSWORD '%s'" % (username, password)
    excute_query(sql, use_sudo=True)