Программа оценок с использованием, если еще

print("Grade List")
print ("==========")
def gradeAssign(marks):
    assert marks>=0 and marks<=100
    
    if marks>=90:
        grade="A"
    elif marks>=70:
        grade="B"
    elif marks>=50:
        grade="C"
    elif marks>=40:
        grade="D"
    else:
        grade="F"
    
    return grade
    
def main():
    marks = float(input('Enter your marks: '))
    print("Marks: ", marks, "\nGrade: ", gradeAssign(marks))
    
main()
Outrageous Ostrich