I am new to python coding and i do not understand how to use a variable from another method - python-3.x

Question

Here is what i have tried:
I do not understand how can i use a variable from another method of same class. Also please explain how can i use a variable from a method in different class. I tried searching but could not find a solution. So what i did to pass the test cases is to copy code from calculate_percentage and paste it in find_grade method. It worked but i think this is the worst method. So please tell a possible solution.
Thanks
#!/bin/python3
#Enter your code here. Read input from STDIN. Print output to STDOUT
class Student:
def __init__(self,roll,name,marks_list):
self.roll=roll
self.name=name
self.marks_list=marks_list
def calculate_percentage(self):
length=len(self.marks_list)
sum=0
for i in self.marks_list:
sum+=i
percent=sum/length
return int(percent)
def find_grade(self,percent):
if percent>=80:
return 'A'
elif percent>=60 and percent<80:
return 'B'
elif percent>=40 and percent<60:
return 'C'
elif percent<40:
return 'F'
if __name__ == '__main__':
roll=int(input())
name=input()
count=int(input())
marks=[]
for i in range(count):
marks.append(int(input()))
s=Student(roll,name,marks)
print(s.calculate_percentage())
print(s.find_grade())
i am getting the error:
print(s.find_grade())
TypeError: find_grade() missing 1 required positional argument: 'percent'

Answer 1

Thanks for every one who answered but i found the answer:
i just need to put self.percent
or percent=self.calculate_percentage() to call the method and use the variables

Answer 2

The assumption would be that the marks are x/100 scale while otherwise your percentage will be incorrect.
As said above, you need to pass the variable percent back to the function since it is not known in the class, it is only returned.
print(s.find_grade(s.calculate_percentage()))
or if the percentage is a class variable you can rewrite it into the class like this:
from statistics import mean
class Student2:
def __init__(self,roll,name,marks_list):
self.roll=roll
self.name=name
self.marks_list=marks_list
def calculate_percentage(self):
self.percent=mean(marks)
return int(self.percent)
def find_grade(self):
if self.percent>=80:
return 'A'
elif self.percent>=60 and self.percent<80:
return 'B'
elif self.percent>=40 and self.percent<60:
return 'C'
elif self.percent<40:
return 'F'
percent = int(0)
# test variables
vRoll = 2
vName = 'student'
vCount= 2
vMarks= [100, 75]
# main
if __name__ == '__main__':
roll=vRoll
name=vName
count=vCount
marks=vMarks
s2=Student2(roll,name,marks)
print(s2.calculate_percentage()) # 87
print(s2.find_grade()) # A