Remove every namespace attribute in a lxml.etree.tostring() [duplicate]

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• How to tell lxml.etree.tostring(element) not to write namespaces in python? 3 answers

I'm trying to print out portions of an xml document for documentation purpose in a bigger program.

In these prints, I do not need any namespace attributes and I would like to remove them for better readability.

I started with:

from lxml import etree, objectify

xmlstring = """
<root ns="http://ns.dettorer.net" xmlns="http://ift.tt/1u1q0X5" xmlns:scp="http://ift.tt/1u1q2OK">
    <tag att='foo' att2='bar' />
    <tag att='bar' att2='foo' />
</root>
"""

xml = etree.XML(xmlstring)

for sub_xml in xml:
    print(etree.tounicode(sub_xml))

which gives:

<tag xmlns="http://ift.tt/1u1q0X5" xmlns:scp="http://ift.tt/1u1q2OK" att="foo" att2="bar"/>
<tag xmlns="http://ift.tt/1u1q0X5" xmlns:scp="http://ift.tt/1u1q2OK" att="bar" att2="foo"/>

I've found lxml.objectify.deannotate in this question which almost gives what I want:

working_xml = copy.deepcopy(xml)
objectify.deannotate(working_xml, cleanup_namespaces=True)
for sub_xml in working_xml:
    print(etree.tounicode(sub_xml))

But the xmlns attribute is still there:

<tag xmlns="http://ift.tt/1u1q0X5" att="foo" att2="bar"/>
<tag xmlns="http://ift.tt/1u1q0X5" att="bar" att2="foo"/>

I tried to remove it with etree.strip_attributes(sub_xml, 'xmlns') (which simply doesn't remove it), sub_xml.attrib.pop('xmlns') and del sub_xml.attrib['xmlns'] (which both raise a KeyError). I guess it's because xmlns is not actually an attribute of my elements.

Is there a way to either tell lxml.objectify.deannotate to also remove that xmlns inherited attribute or to remove it after that? I've also considered using a regexp to remove the attribute after the .tounicode conversion, but I'm seeking a cleaner and more sensible way.

I also cannot make a deep copy of the whole xml document (and then remove the xmlns attribute in the root node) since the document and my program structure are much bigger than this example.