```ruby
require 'curb'
require 'digest'
require 'tempfile'

module Sufeed
  def self.checksum(url)
    file = Tempfile.new('sufeed')
    redirected = location(url)
    puts "Redirected to #{redirected}" if url != redirected
    Curl::Easy.download(redirected, file.path)

    sha256 = Digest::SHA2.file(file.path).hexdigest
    return sha256
  end
end
```

Fix a bug that doesn't follow a redirect chain
user
```ruby
require 'curb'
require 'digest'
require 'tempfile'

module Sufeed
  def self.checksum(url)
    file = Tempfile.new('sufeed')
    Curl::Easy.download(url, file.path) do |curl|
      curl.follow_location = true
    end
    sha256 = Digest::SHA2.file(file.path).hexdigest
    return sha256
  end
end
```
assistant