memory leak question

[xiaolibuzai-ovo]

I encountered a memory leak while using pdmupdf(1.25.4), where the service memory continuously increases even when it is no longer in use. Could you please let me know if there are any issues with the usage of these functions?

class PymupdfProcess:

    def __init__(self, ctx: context.Context, file_path: str = None, file_bytes: BytesIO = None):
        self.ctx = ctx
        self.cos_cli = CosProxy()
        if file_path:
            self.file_path = file_path
            self.doc = pymupdf.open(file_path)
        elif file_bytes:
            self.file_path = None
            self.doc = pymupdf.open(stream=file_bytes, filetype="pdf")
        else:
            raise ValueError("Either file_path or url must be provided")

    async def get_page_num(self):
        return len(self.doc)

    async def get_pix_map(self, page_num: int) -> bytes:
   
        page = self.doc[page_num]
        pix = page.get_pixmap(dpi=300)
        image_bytes = pix.tobytes("png")
        return image_bytes

    async def get_metadata(self) -> Dict[int, PageMetaData]:

        metadata = {}
        for i in range(len(self.doc)):
            page = self.doc[i]
            page_rect = page.rect
            metadata[i] = PageMetaData(page_rect.width, page_rect.height)

        return metadata

    async def page_erasure(self, page_num: int, blocks: List[pb.TextItem], del_links: bool = True):

        page = self.doc[page_num]
        if del_links:
            for link in page.get_links():
                page.delete_link(link)

        for i in range(len(blocks)):
            block = blocks[i]
            white = pymupdf.pdfcolor["white"]
            page.draw_rect(tuple(block.bbox), color=None, fill=white)

    async def restore(self, page_num: int, blocks: List[pb.TextItem]):

        page = self.doc[page_num]
        for i in range(len(blocks)):
            block = blocks[i]
            try:
                page.insert_htmlbox(tuple(block.bbox), block.text, css=block.css, rotate=block.rotate, archive=archive)
            except OverflowError as e:
                logger.error_context(self.ctx, f"restore err: {str(e)}")
                continue

    async def save(self, file_id: str) -> str:
        self.doc.subset_fonts(verbose=True)  # build subset fonts to reduce file size
        pdf_bytes = self.doc.tobytes(garbage=4)
        cos_key = await self.cos_cli.upload(self.ctx, pdf_bytes, file_id)
        url = await self.cos_cli.get_access_url(self.ctx, cos_key)
        return url

    async def close(self):
        if self.doc:
            self.doc.close()
            self.doc = None