<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def ask_str(msg="Enter a string", dft=None, vld=None, shw=True, blk=True, hlp=None):
 """Prompts the user for a string."""

    vld = vld or [str]
    return ask(msg, dft=dft, vld=vld, shw=shw, blk=blk, hlp=hlp)