<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def set_is_playable(self, is_playable):
        '''Sets the listitem's playable flag'''
        value = 'false'
        if is_playable:
            value = 'true'
        self.set_property('isPlayable', value)
        self.is_folder = not is_playable