def grab_input(self):
        """Get more input if possible."""
        if not self.file: return
        if self.pos - len(self.input) >= MIN_WINDOW: return

        data = self.file.read(MIN_WINDOW)
        if data is None or data == "":
            self.file = None

        # Drop bytes from the start, if necessary.
        if self.pos > 2*MIN_WINDOW:
            self.del_pos += MIN_WINDOW
            self.del_line += self.input[:MIN_WINDOW].count("\n")
            self.pos -= MIN_WINDOW
            self.input = self.input[MIN_WINDOW:] + data
        else:
            self.input = self.input + data
dataset/ETHPy150Open smurfix/yapps/yapps/runtime.py/Scanner.grab_input/swapped operands of `-`