Executes a piped command and get the lines of the output in a list

        :param stderr: where to put stderr
        :return: output of command

def get_complex_output(self, stderr=STDOUT):
        """Executes a piped command and get the lines of the output in a list

        :param stderr: where to put stderr
        :return: output of command
        """
        proc = Popen(self.cmd, shell=True, stdout=PIPE, stderr=stderr)
        return proc.stdout.readlines()