Initializes the auth settings for accessing MyAnimelist through its
    official API from a given filename.
    :param filename The name of the file containing your MyAnimeList
                    credentials
                    REQUIREMENTS: The file must...
                        ...username for your MAL account.
                        ...password for your MAL account.
                        ...Have both your username  and password
                        ...separated by newline(s) or space(s).
    :return A tuple containing your credentials.

def load_auth_from_file(filename):
    """Initializes the auth settings for accessing MyAnimelist through its
    official API from a given filename.
    :param filename The name of the file containing your MyAnimeList
                    credentials
                    REQUIREMENTS: The file must...
                        ...username for your MAL account.
                        ...password for your MAL account.
                        ...Have both your username  and password
                        ...separated by newline(s) or space(s).
    :return A tuple containing your credentials.
    """
    with open(filename) as auth_file:
        lines = auth_file.read().splitlines()
        lines = [line.strip() for line in lines if len(line) != 0]
        if len(lines) == 2:
            credentials = (lines[0], lines[1])
        elif len(lines) == 1:
            user_pass = lines[0].split()
            credentials = (user_pass[0], user_pass[1])
        elif len(lines) == 0 or len(lines) > 2:
            raise ValueError(constants.INVALID_AUTH_FILE)

        if helpers.verif_auth(credentials, header):
            return credentials
        else:
            raise ValueError(constants.INVALID_CREDENTIALS)