<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def run(self, force=False):
 """ Run all pending tasks; 'force' will run all tasks whether they're pending or not. """

        now = time.time()
        for func, spec in self.tasks.items():
            if force or now >= spec.get('next_run', 0):
                func()
                spec['next_run'] = now + spec['interval']