def _read_and_append(self, filepath):  # pylint: disable=no-self-use
        # Open up filepath differently depending on if it already exists
        if os.path.isfile(filepath):
            op_fd = open(filepath, "r+")
            lines = op_fd.read().splitlines()
        else:
            lines = []
            op_fd = open(filepath, "w")

        return op_fd, lines
Reads the file lines and returns a file obj.
dataset/ETHPy150Open letsencrypt/letsencrypt/certbot/reverter.py/Reverter._read_and_append