```ruby
require 'formula'

class CfCli < Formula
  homepage 'https://github.com/cloudfoundry/cli'
  head 'https://cli.run.pivotal.io/edge?arch=macosx64&source=homebrew'
  url 'https://cli.run.pivotal.io/stable?release=macosx64-binary&version=6.18.0&source=homebrew'
  version '6.18.0'
  sha256 '9a60d7542a7cbc46b31aa82fea91b7fc06fbdbecd09e39a31ce01c44cd7065c5'

  depends_on :arch => :x86_64

  conflicts_with "pivotal/tap/cloudfoundry-cli", :because => "the Pivotal tap ships an older cli distribution"
  conflicts_with "caskroom/cask/cloudfoundry-cli", :because => "the caskroom tap is not the official distribution"

  def install
    bin.install 'cf'
  end

  test do
    system "#{bin}/cf"
  end
end
```

Update the sha256 of 6.18.0
user
```ruby
require 'formula'

class CfCli < Formula
  homepage 'https://github.com/cloudfoundry/cli'
  head 'https://cli.run.pivotal.io/edge?arch=macosx64&source=homebrew'
  url 'https://cli.run.pivotal.io/stable?release=macosx64-binary&version=6.18.0&source=homebrew'
  version '6.18.0'
  sha256 '0fc455d33b990e8c463e77f6a3218e7d8df1d54a851276985318254dcfb3576f'

  depends_on :arch => :x86_64

  conflicts_with "pivotal/tap/cloudfoundry-cli", :because => "the Pivotal tap ships an older cli distribution"
  conflicts_with "caskroom/cask/cloudfoundry-cli", :because => "the caskroom tap is not the official distribution"

  def install
    bin.install 'cf'
  end

  test do
    system "#{bin}/cf"
  end
end
```
assistant