Canvas grades file Python context object

canvasgrades.py

import csv
from pathlib import Path


class CanvasGradeFile():
    def __init__(self, file: Path):
        self.file = file

    def __enter__(self):
        with self.file.open('r') as f:
            self.reader = csv.DictReader(f)
            self.rows = list([r for r in self.reader])
            self.fieldnames = self.reader.fieldnames

        print(f"Gradebook loading assignments ...")
        self.assignments = {}
        self.maxpoints = {}
        for i, (assignment, points) in enumerate(self.rows[0].items()):
            print(f"{i}: {points} points, \"{assignment}\"")
            self.assignments[assignment] = i
            self.maxpoints[assignment] = points

        return self

    def __exit__(self, exc_type, exc_value, traceback):
        with self.file.open('w') as f:
            writer = csv.DictWriter(f, self.fieldnames)
            writer.writeheader()
            for r in self.rows:
                writer.writerow(r)

example.py

# example usage:

assignment = "Practice Assignment (12345678)"

with CanvasGradeFile(Path(args.gradefile)) as gradebook: 
    for i, graderow in enumerate(gradebook.rows):
        netid = graderow[canvas_netid_col]

        # determine a grade or something

        graderow[assignment] = 10

# now you can upload the modified CSV right back into canvas to update the grades