Getting the email body using python

I'm quite new at this, but I've been trying to get the email body using python and I've tried almost all of the examples out there and I was able, with:

original = email.message_from_string(response_part[1].decode('utf-8'), policy=policy.default)

         data1 = original.get_body('text/plain')

to get this:

Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64

SGkNCg==

in which the last line is actual my email body encoded with base64 but what I'm trying to do now is to actually get just the last line:

SGkNCg==

any suggestions?