<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def guard_rollback_to_open(worksheet):
 """Return whether 'rollback_to_receive' transition can be performed or not """

    for analysis in worksheet.getAnalyses():
        if api.get_review_status(analysis) in ["assigned"]:
            return True
    return False