Python Regex List Creation

Here is a snippet of my code:

    blahblahblah...
    blah[]
    for link in goodies.soup.find_all('a'):
       blah.append(link.get('href'))
       blah=list(set(blah))

which gives my list of urls. So now I use a regex to search for the relevant urls which I want in a list:

     for r in blah:
     capture=re.findall(r'https://.*', r)
     print (capture)

which prints the results as:

    []
    ['https://blah.org/plugins/blahblahblahblah/']
    []
    []
    ['https://blah.org/plugins/blahblahblah/']

What I am trying to do is create a list from these results. When I attempt to do this, I always run into a brickwall:

    for r in blah:
        capture=re.findall(r'https://.*', r)
        purls=[]
        purls.append(capture)
    purls
    [[]]
    for r in blah:
        capture=re.findall(r'https://.*', r)
        purls=[]
           for a in capture:
               purls.append(a)
    purls
    []

This is the closest thing I could come up with:

    for r in blah:
         capture=re.findall(r'https://.*', r)
         rolos=capture[:]
         print rolos
    []
    ['https://blah.org/plugins/blahblahblahblah/']
    []
    []
    ['https://blah.org/plugins/blahblahblah/']
    whos
    rolos           list      n=0

But as you can see, it didnt create the list???? What am I doing wrong and how can this be accomplished ?

---------- Post updated at 05:01 PM ---------- Previous update was at 04:34 PM ----------

so it turned out to be the +=, which is the increment operator

    for r in blah:
      capture=re.findall(r'https://.*', r)
      rolos+=capture[:]

Thanks to dslackw for providing this insane resolution. I still cant believe it.