Set text in bold with office open xml in python docx template

Question

I have the following code that grabs a word template and fills the required values inside of it:

text =  "<w:r><w:rPr><w:b/></w:rPr><w:t>Test Text</w:t></w:r><w:r><w:t> < /w:t> </w:r>"
context = {
    "content": text
}
template = DocxTemplate("document.docx")
template.render(context)
template.save(filename)

I need to set to bold part of that text and when I apply that xml format, I get the following:

And when I try to change it to this:

text =  "<w:r><w:rPr><w:b/></w:rPr><w:t>Test Text</w:t></w:r>"

the document has invalid format.

So, how can I set part of the text to bold correctly?

Thanks