# Buggy code
def get_output(self, cmd, output, timeout=None):
    """Get output from command.

    :param cmd: Command to get output from
    :type cmd: :py:class:`gevent.Greenlet`
    :param output: Dictionary containing
      :py:class:`pssh.output.HostOutput` values to be updated with output
      from cmd
    :type output: dict
    :rtype: None"""
    try:
        (channel, host, stdout, stderr, stdin) = cmd.get(timeout=timeout)
    except Exception as ex:
        host = ex.host
        self._update_host_output(
            output, host, None, None, None, None, None, cmd, exception=ex
        )
        raise
    self._update_host_output(
        output, host, self._get_exit_code(channel), channel, stdout, stderr, stdin, cmd
    )


# Traceback (ValueError)
Traceback (most recent call last):
File "./aws-instances", line 172, in <module>
main()
File "./aws-instances", line 73, in main
facts = remote_facts(ips)
File "./aws-instances", line 146, in remote_facts
out_kern = client.run_command('uname -r')
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/native/parallel.py", line 223, in run_command
greenlet_timeout=greenlet_timeout)
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/base_pssh.py", line 96, in run_command
self.get_output(cmd, output, timeout=greenlet_timeout)
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/base_pssh.py", line 141, in get_output
(channel, host, stdout, stderr, stdin) = cmd.get(timeout=timeout)
File "src/gevent/greenlet.py", line 709, in gevent._greenlet.Greenlet.get
File "src/gevent/greenlet.py", line 317, in gevent._greenlet.Greenlet._raise_exception
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/gevent/_compat.py", line 47, in reraise
raise value.with_traceback(tb)
File "src/gevent/greenlet.py", line 766, in gevent._greenlet.Greenlet.run
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/native/parallel.py", line 237, in _run_command
raise ex
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/native/parallel.py", line 233, in _run_command
use_pty=use_pty, encoding=encoding, timeout=timeout)
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/native/single.py", line 442, in run_command
channel = self.execute(_command, use_pty=use_pty)
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/native/single.py", line 324, in execute
channel = self.open_session() if channel is None else channel
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/pssh/clients/native/single.py", line 297, in open_session
wait_select(self.session)
File "pssh/native/_ssh2.pyx", line 171, in pssh.native._ssh2.wait_select
File "/home/user/do-aws-ec2-facts/aws/lib64/python3.6/site-packages/gevent/select.py", line 145, in select
sel_results = _original_select(rlist, wlist, xlist, 0)
ValueError: filedescriptor out of range in select()

# Fixed code
def get_output(self, cmd, output, timeout=None):
    """Get output from command.

    :param output: Dictionary containing
      :py:class:`pssh.output.HostOutput` values to be updated with output
      from cmd
    :type output: dict
    :rtype: None
    """
    warn(_get_output_depr_notice)
    if not isinstance(output, dict):
        raise ValueError(
            "get_output is for the deprecated dictionary output only. "
            "To be removed in 2.0.0"
        )
    try:
        (channel, host, stdout, stderr, stdin) = cmd.get(timeout=timeout)
    except Exception as ex:
        host = ex.host
        self._update_host_output(
            output, host, None, None, None, None, None, cmd, exception=ex
        )
        raise
    self._update_host_output(
        output, host, self._get_exit_code(channel), channel, stdout, stderr, stdin, cmd
    )