Why is it optional to save credentials when pytr crashes as soon as you refuse to save?

[C0D3D3V]

Description of the bug
Why is it optional to save credentials when pytr crashes as soon as you refuse to save?

To Reproduce
Steps to reproduce the behavior:

1. Run pytr login
2. Refuse to save the credentials
3. See error

Expected behavior
Would be great if the program works without me saving the credentials

Error log

C:\Users\Virtual>pytr login
13:07:02 Credentials file not found
Please enter your TradeRepbulic phone number in the format +4912345678:
+4912345678
Please enter your TradeRepbulic pin:
0000
Save credentials? Type "y" to save credentials:
n
13:07:24 Credentials not saved
Traceback (most recent call last):
  File "c:\users\virtual\appdata\local\programs\python\python38-32\lib\site-packages\pytr\api.py", line 89, in __init__
    with open(CREDENTIALS_FILE, 'r') as f:
FileNotFoundError: [Errno 2] No such file or directory: 'C:\\Users\\Virtual\\.pytr\\credentials'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\virtual\appdata\local\programs\python\python38-32\lib\runpy.py", line 194, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "c:\users\virtual\appdata\local\programs\python\python38-32\lib\runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "C:\Users\Virtual\AppData\Local\Programs\Python\Python38-32\Scripts\pytr.exe\__main__.py", line 7, in <module>
  File "c:\users\virtual\appdata\local\programs\python\python38-32\lib\site-packages\pytr\main.py", line 143, in main
    login(phone_no=args.phone_no, pin=args.pin, web=weblogin)
  File "c:\users\virtual\appdata\local\programs\python\python38-32\lib\site-packages\pytr\account.py", line 61, in login
    tr = TradeRepublicApi()
  File "c:\users\virtual\appdata\local\programs\python\python38-32\lib\site-packages\pytr\api.py", line 94, in __init__
    raise ValueError(f'phone_no and pin must be specified explicitly or via {CREDENTIALS_FILE}')
ValueError: phone_no and pin must be specified explicitly or via C:\Users\Virtual\.pytr\credentials

Environment

• OS: Windows
• Version: pytr-0.0.9