what batch CLI command for Windows 10 to convert folder with gyu file to png?
how to use it since command "python gyu2png.py convert_gyu_to_png('example.gyu', 'example.png')" not working and nothing happens when I use it?
```
import os
import struct
from io import BytesIO
from PIL import Image

class GyuMetaData:
    def __init__(self, flags, compression_mode, key, bpp, width, height, data_size, alpha_size, palette_size):
        self.flags = flags
        self.compression_mode = compression_mode
        self.key = key
        self.bpp = bpp
        self.width = width
        self.height = height
        self.data_size = data_size
        self.alpha_size = alpha_size
        self.palette_size = palette_size

class GyuFormat:
    def __init__(self):
        self.signature = 0x1A555947  # 'GYU'

    def read_meta_data(self, stream):
        stream.seek(4)
        flags = struct.unpack('<H', stream.read(2))[0]
        compression_mode = struct.unpack('<H', stream.read(2))[0]
        key = struct.unpack('<I', stream.read(4))[0]
        bpp = struct.unpack('<i', stream.read(4))[0]
        width = struct.unpack('<I', stream.read(4))[0]
        height = struct.unpack('<I', stream.read(4))[0]
        data_size = struct.unpack('<i', stream.read(4))[0]
        alpha_size = struct.unpack('<i', stream.read(4))[0]
        palette_size = struct.unpack('<i', stream.read(4))[0]
        return GyuMetaData(flags, compression_mode, key, bpp, width, height, data_size, alpha_size, palette_size)

    def read(self, stream):
        meta = self.read_meta_data(stream)
        stream.seek(0x24)
        palette = self.read_palette(stream, meta.palette_size) if meta.palette_size else None
        packed_data = stream.read(meta.data_size)
        if meta.key != 0xFFFFFFFF:
            packed_data = self.deobfuscate(packed_data, meta.key)
        if meta.compression_mode == 0x0100:
            image_data = packed_data
        else:
            image_data = self.unpack_data(packed_data, meta)
        if meta.alpha_size:
            image_data = self.read_alpha(image_data, stream, meta)
        return self.create_image(image_data, meta, palette)

    def read_palette(self, stream, palette_size):
        return [struct.unpack('<B', stream.read(1))[0] for _ in range(palette_size)]

    def deobfuscate(self, data, key):
        # Placeholder for deobfuscation logic
        return data

    def unpack_data(self, packed_data, meta):
        # Placeholder for unpacking logic
        return packed_data

    def read_alpha(self, image_data, stream, meta):
        # Placeholder for alpha channel reading logic
        return image_data

    def create_image(self, image_data, meta, palette):
        if meta.bpp == 8:
            mode = 'P'
            image = Image.frombytes(mode, (meta.width, meta.height), image_data)
            image.putpalette(palette)
        else:
            mode = 'RGBA' if meta.alpha_size else 'RGB'
            image = Image.frombytes(mode, (meta.width, meta.height), image_data)
        return image

    def write(self, image, output_path):
        # Placeholder for writing logic
        pass

def convert_gyu_to_png(input_path, output_path):
    with open(input_path, 'rb') as f:
        gyu_format = GyuFormat()
        image = gyu_format.read(f)
        image.save(output_path, 'PNG')

def convert_png_to_gyu(input_path, output_path):
    image = Image.open(input_path)
    gyu_format = GyuFormat()
    gyu_format.write(image, output_path)

# Example usage
# convert_gyu_to_png('example.gyu', 'example.png')
# convert_png_to_gyu('example.png', 'example.gyu')