<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def data_check(self, participant):
 """Make sure each trial contains exactly one chosen info."""

        infos = participant.infos()
        return len([info for info in infos if info.chosen]) * 2 == len(infos)