<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def pre_create(sender, model):
 """ Callback before creating a new login Without a password during create we are forced to set the password to something random & complex. """


    if isinstance(model, Model) and not model.password:
        model.password = random_str()