'grade student response.'

def get_score(self, student_answers):

    if (not self.has_partial_credit):
        return self.grade_without_partial_credit(student_answers=student_answers)
    graders = {'points': self.grade_via_points, 'false': self.grade_without_partial_credit}
    if (len(self.credit_type) > 1):
        raise LoncapaProblemError('Only    one    type    of    partial    credit    is    allowed    for    Multiple    Choice    problems.')
    if (self.credit_type[0] not in graders):
        raise LoncapaProblemError(('partial_credit    attribute    should    be    one    of:    ' + ','.join(graders)))
    return graders[self.credit_type[0]](student_answers=student_answers)
