```ruby
class Visit < Cask
  url 'http://portal.nersc.gov/svn/visit/trunk/releases/2.7.0/VisIt-2.7.0-x86_64-installer.dmg'
  homepage 'https://wci.llnl.gov/codes/visit/home.html'
  version '2.7.0'
  sha1 'be44ee53695553396895154e7c9916bb670f772c'
  link 'VisIt.app'
end
```

Update VisIt to version 2.7.1.
user
```ruby
class Visit < Cask
  url 'http://portal.nersc.gov/svn/visit/trunk/releases/2.7.1/VisIt-2.7.1.dmg'
  homepage 'https://wci.llnl.gov/codes/visit/home.html'
  version '2.7.1'
  sha1 '051de3d0439fde1f20a6f1c952c006a9a91536fc'
  link 'VisIt.app'
end
```
assistant