class Mixlib::ShellOut

ShellCommandFailed always
=== Raises
is highly encouraged.
default explanation is very generic, providing a more informative message
+msg+: A String to use as the basis of the exception message. The
=== Arguments
command's stdout, stderr, and exitstatus to the exception message.
Raises a ShellCommandFailed exception, appending the

def invalid!(msg=nil)
  msg ||= "Command produced unexpected results"
  raise ShellCommandFailed, msg + "\n" + format_for_exception
end