Python signxml 自定义命名空间

Question

I am trying to change the namespace that signxml creates when I sign an xml document in python. currently it signs the signature with ds: and I would like to change it to dsig:

I am using

signed_root = XMLSigner(signature_algorithm='rsa-sha512',method=signxml.methods.enveloping,digest_algorithm="sha512").sign(root, key=secret)

and I get something like

<ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"><ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2006/12/xml-c14n11"/>

but need it to be

<dsig:Signature xmlns:dsig="http://www.w3.org/2000/09/xmldsig#">dsig:SignedInfo<dsig:CanonicalizationMethod Algorithm="http://www.w3.org/2006/12/xml-c14n11"/>

I am sure it is something to do with namespaces but can't find where to change it

Thanks