class Mixlib::ShellOut

::ShellCommandFailed::: via +invalid!+
=== Raises
nil::: always returns nil when it does not raise
=== Returns
which raises an Exception.
+exitstatus+ is not in the list of +valid_exit_codes+, calls +invalid!+,
Checks the +exitstatus+ against the set of +valid_exit_codes+. If

def error!
  unless Array(valid_exit_codes).include?(exitstatus)
    invalid!("Expected process to exit with #{valid_exit_codes.inspect}, but received '#{exitstatus}'")
  end
end