Problem with wsgiref.headers.Headers

[Phil]

I am having an issue with wsgiref.headers.Headers.

For example, if I do this...

from wsgiref.headers import Headers
list = []
wrapper = Headers(list)
wrapper['content-type'] = "text/html"
print(list)
print(wrapper)

I get an empty list printed, and then the correct result for wrapper
printed.

Am I misunderstanding the documentation?

class wsgiref.headers.Headers(headers)
Create a mapping-like object wrapping headers, which must be a list of
header name/value tuples as described in PEP 333. Any changes made to
the new Headers object will directly update the headers list it was
created with.

Thanks for any help,

Phil