Trouble understanding how the Django save() handles *args

Was fighting yesterday with the issue of importing pics from URL to the Django model. Was able to come up with a working solution, but still don't know how this is works. How a save func knows what kind of *args it could process and in what order? Because when I changed places for picture object and filename it didn't work TypeError: join() argument must be str or bytes, not 'File'. Could not understand it reading the docs - https://docs.djangoproject.com/en/2.1/_modules/django/db/models/base/#Model.save. The script below putting NHL players names, id and profile pics to my Player model. Any help?

the commands file:

import urllib.request as urllib
import requests

from django.core.management.base import BaseCommand, CommandError
from django.core.files import File

from players.models import Player


URL_PLAYERS = 'http://www.nhl.com/stats/rest/{}'
URL_PICS = 'https://nhl.bamcontent.com/images/headshots/current/168x168/{}.jpg'


class Command(BaseCommand):

    def import_player(self, data):
        id_ = data["playerId"]
        content = urllib.urlretrieve(URL_PICS.format(id_))
        pic = File(open(content[0], 'rb'))  # do I need to close the file here?
        file = f'{data["playerName"]}.jpg'
        player = Player(name=data["playerName"], nhl_id=id_)
        player.save()
        player.image.save(file, pic)


    def handle(self, *args, **options):

        params = {"isAggregate": "false",
                  "reportType": "basic",
                  "isGame": "false",
                  "reportName": "skaterpercentages",
                  "cayenneExp": "gameTypeId=2 and seasonId=20182019"}

        response = requests.get(url=URL_PLAYERS.format("skaters"),
                                params=params)

        response.raise_for_status()
        data = response.json()["data"]

        for player in data:
            self.import_player(player)

the models file:

from django.db import models

class Player(models.Model):
    name = models.CharField(max_length=128)
    nhl_id = models.IntegerField()  #(unique=True)
    image = models.ImageField(default='default.jpg', upload_to='players_pics')

    def __str__(self):
        return f'{self.name}'

Just to not to leave the question unanswered. As @Daniel Roseman suggested I confused two different methods. Was actually using the FileField save method, but thought I was using Model.save method. So, was looking at the wrong documentation.