<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_missing_dependencies(self, broker):
 """ Gets required and at-least-one dependencies not provided by the broker. """

        missing_required = [r for r in self.requires if r not in broker]
        missing_at_least_one = [d for d in self.at_least_one if not set(d).intersection(broker)]
        if missing_required or missing_at_least_one:
            return (missing_required, missing_at_least_one)