使用XMLSec库签名含指定URI的XML文档失败问题求助

各位大佬好，我最近在用XMLSec库给NFCom格式的XML文件做签名，要求必须使用指定算法，同时要把<infNFCom>元素的Id属性作为引用的URI。但碰到一个特别诡异的问题：当我给add_reference方法的uri参数填值（格式是#{id_nfcom}）时，文档完全签不了；可要是把这个URI留空，签名就能正常生成。我已经反复核对过Id属性的取值，确认和XML里的内容完全一致，实在搞不懂哪里出问题了。

示例ID：#NFCom43253123827184000163620017659731731076965182

下面是我的签名代码，重点是标记出来的那部分：

def assinar_xml(xml_tree, certificado_pem):
    root = xml_tree.getroot()
    
    inf_nfcom = root.find(".//{http://www.portalfiscal.inf.br/NFCom}infNFCom")
    if inf_nfcom is None:
        raise ValueError("Elemento <infNFCom> não encontrado no XML.")

    id_nfcom = inf_nfcom.get("Id")
    if not id_nfcom:
        raise ValueError("Atributo 'Id' não encontrado no elemento <infNFCom>.")

    signature = xmlsec.template.create(
        root, xmlsec.Transform.C14N, xmlsec.Transform.RSA_SHA1
    )
    
    # 就是这行代码，填了uri就签不了
    ref = xmlsec.template.add_reference(
        signature, xmlsec.constants.TransformSha1, uri=f"#{id_nfcom}"
    )

    xmlsec.template.add_transform(ref, xmlsec.Transform.ENVELOPED)
    xmlsec.template.add_transform(ref, xmlsec.Transform.C14N)

    key_info = xmlsec.template.ensure_key_info(signature)
    x509_data = xmlsec.template.add_x509_data(key_info)
    xmlsec.template.x509_data_add_certificate(x509_data)

    root.append(signature)
    
    ctx = xmlsec.SignatureContext()
    
    key = None
    try:
        key = xmlsec.Key.from_file(certificado_pem, xmlsec.constants.KeyDataFormatPem)
        print("Chave carregada com sucesso!")
    except Exception as e:
        print(f"Erro ao carregar a chave: {e}")

    if key is None:
        raise ValueError("A chave não foi carregada corretamente.")

    ctx.key = key

    ctx.sign(signature)
    
    return xml_tree

签名前的XML文档内容如下：

<NFCom xmlns="http://www.portalfiscal.inf.br/NFCom">
  <infNFCom Id="NFCom43253123827184000163620017659731731076965182" versao="1.00">
    <ide>
      <cUF>43</cUF>
      <tpAmb>2</tpAmb>
      <mod>62</mod>
      <serie>1</serie>
      <nNF>765973173</nNF>
      <cNF>7696518</cNF>
      <cDV>2</cDV>
      <dhEmi>2025-01-31T11:56:18-03:00</dhEmi>
      <tpEmis>1</tpEmis>
      <nSiteAutoriz>0</nSiteAutoriz>
      <cMunFG>3205309</cMunFG>
      <finNFCom>0</finNFCom>
      <tpFat>0</tpFat>
      <verProc>1.00</verProc>
    </ide>
    <emit>
      <CNPJ>23827184005463</CNPJ>
      <IE>9071339235</IE>
      <IEUFDest>321</IEUFDest>
      <CRT>1</CRT>
      <xNome>TELECOM LTDA ME</xNome>
      <xFant>Telecom</xFant>
      <enderEmit>
        <xLgr>AV. PRESIDENTE KENNEDY</xLgr>
        <nro>845</nro>
        <xBairro>Centro</xBairro>
        <cMun>4117909</cMun>
        <xMun>Palotina</xMun>
        <CEP>85950000</CEP>
        <UF>PR</UF>
      </enderEmit>
    </emit>
    <dest>
      <xNome>Cliente de Telecomunicações Ltda</xNome>
      <CNPJ>98765432000187</CNPJ>
      <indIEDest>1</indIEDest>
      <IE></IE>
      <IM>1</IM>
      <enderDest>
        <xLgr>Rua das Comunicações</xLgr>
        <nro>123</nro>
        <xBairro>Centro</xBairro>
        <cMun>3205309</cMun>
        <xMun>Vitória</xMun>
        <CEP>85950000</CEP>
        <UF>ES</UF>
      </enderDest>
    </dest>
    <assinante>
      <iCodAssinante>01</iCodAssinante>
      <tpAssinante>1</tpAssinante>
      <tpServUtil>4</tpServUtil>
    </assinante>
    <det nItem="1">
      <prod>
        <cProd>001</cProd>
        <xProd>Serviço de Internet Banda Larga</xProd>
        <cClass>0400401</cClass>
        <CFOP>5303</CFOP>
        <uMed>2</uMed>
        <qFaturada>100.00</qFaturada>
        <vItem>100.00</vItem>
        <vProd>100.00</vProd>
      </prod>
      <imposto>
        <ICMS00>
          <CST>00</CST>
          <vBC>10.00</vBC>
          <pICMS>18.00</pICMS>
          <vICMS>1.80</vICMS>
        </ICMS00>
      </imposto>
    </det>
    <total>
      <vProd>100.00</vProd>
      <ICMSTot>
        <vBC>10.00</vBC>
        <vICMS>1.80</vICMS>
        <vICMSDeson>1.00</vICMSDeson>
        <vFCP>1.00</vFCP>
      </ICMSTot>
      <vCOFINS>1.00</vCOFINS>
      <vPIS>1.00</vPIS>
      <vFUNTTEL>1.00</vFUNTTEL>
      <vFUST>1.00</vFUST>
      <vRetTribTot>
        <vRetPIS>1.00</vRetPIS>
        <vRetCofins>1.00</vRetCofins>
        <vRetCSLL>1.00</vRetCSLL>
        <vIRRF>1.00</vIRRF>
      </vRetTribTot>
      <vDesc>0.00</vDesc>
      <vOutro>1.00</vOutro>
      <vNF>100.00</vNF>
    </total>
  </infNFCom>
  <infNFComSupl>
    <qrCodNFCom>http://dfe-portal.svrs.rs.gov.br/NFCom/QRCode?chNFCom=43120201234567890123456789012345678901234567&amp;amp;tpAmb=2</qrCodNFCom>
  </infNFComSupl>
</NFCom>

有没有大佬遇到过类似的问题？麻烦帮我看看哪里出错了，万分感谢！

备注：内容来源于stack exchange，提问作者Renan Akira Escribano