<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def convert_bool(string):
 """Check whether string is boolean. """

    if string == 'True':
        return True, True
    elif string == 'False':
        return True, False
    else:
        return False, False