'return a copy of the source object with
\'before\' and \'after\' wrapped around it.'

def putaround(self, before='', after='', indent=('    ' * 4)):

    before = Source(before)
    after = Source(after)
    newsource = Source()
    lines = [(indent + line) for line in self.lines]
    newsource.lines = ((before.lines + lines) + after.lines)
    return newsource
