Is there any way to get vim to auto wrap python strings at 79 chars?

I found this answer about wrapping strings using parens extremely useful, but is there a way in Vim to make this happen automatically? I want to be within a string, typing away, and have Vim just put parens around my string and wrap it as necessary. For me, this would be a gigantic time saver as I spend so much time just wrapping long strings manually. Thanks in advance.

Example:

1. I type the following text:

   mylongervarname = "my really long string here so please wrap and quote
   automatically"
   

2. Vim automatically does this when I hit column 80 with the string:

   mylongervarname = ("my really long string here so please wrap and "
                      "quote automatically")