I have this code bellow in odoo 16, when I want to print single document/download it works!
But if want to print three or more documents I got this error:

PyPDF2.utils.PdfReadError: Cannot read an empty file

This is my code:

def print_receituario(self):
    report = self.env.ref("dental_clinic.action_dental_prescription_report", False)
    dental_record = self.dental_record_id
    patient = self.dental_record_id.patient_id
    if not (len(dental_record) == 1):
        return
    if len(self) == 1:
        report_name = safe_eval(report.print_report_name, {"object": self})
    else:
        report_name = f"Receituário - {patient.name}"

    pdf_content, _ = (
        self.env["ir.actions.report"]
        .with_context(lang=patient.lang)
        .sudo()
        ._render_qweb_pdf(report.id, self.ids, data={"company_id": self.env.company})
    )
    attachment = self.env["ir.attachment"].create(
        {
            "name": report_name,
            "res_model": "dental.record",
            "res_id": dental_record.id,
            "datas": base64.b64encode(pdf_content),
        }
    )
    return {"type": "ir.actions.act_url", "url": f"/web/content/{attachment.id}"}

Can anyone explain it to me?

Hope to hear you shortly!