<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def grading_value_text(self):
        '''
        A rendering of the grading that is an answer to the question
        "What is the grade?".
        '''
        if self.assignment.is_graded():
            if self.is_grading_finished():
                return str(self.grading)
            else:
                return str('pending')
        else:
            if self.is_grading_finished():
                return str('done')
            else:
                return str('not done')