PermissionError: [Errno 13] Permission denied

import tempfile
import os
 
 
class File(object):
    def __init__(self, file_name, context=''):
        self.file_name = file_name
        self.context = context
        with open(file_name, 'a'):
            pass
 
    def read(self):
        with open(self.file_name, 'r', encoding='utf-8') as f:
            return f.read()
 
    def write(self, line):
        with open(self.file_name, 'w', encoding='utf-8') as f:
            f.write(line)
 
    def save(self):
        with open(self.file_name, 'w', encoding='utf-8') as f:
            f.write(self.context)
 
    def __add__(self, other):
        self.temp = tempfile.NamedTemporaryFile()
        new_file = File(
            file_name=self.temp.name,
            context=self.read() + other.read()
        )
 
    def __str__(self):
        return os.path.abspath(self.file_name)
 
    def __iter__(self):
        return self
 
 
path_to_file = 'some_filename'
file_obj_1 = File(path_to_file + '_1')
file_obj_2 = File(path_to_file + '_2')
file_obj_1.write('line 1\n')
file_obj_2.write('line 2\n')
 
new_file_obj = file_obj_1 + file_obj_2