# Buggy code
def __init__(
    self,
    hosts,
    user=None,
    password=None,
    port=None,
    pkey=None,
    allow_agent=True,
    num_retries=DEFAULT_RETRIES,
    timeout=120,
    pool_size=10,
    host_config=None,
    retry_delay=RETRY_DELAY,
):
    if isinstance(hosts, str) or isinstance(hosts, bytes):
        raise TypeError(
            "Hosts must be list or other iterable, not string. "
            "For example: ['localhost'] not 'localhost'."
        )
    self.allow_agent = allow_agent
    self.pool_size = pool_size
    self.pool = gevent.pool.Pool(size=self.pool_size)
    self.hosts = hosts
    self.user = user
    self.password = password
    self.port = port
    self.pkey = pkey
    self.num_retries = num_retries
    self.timeout = timeout
    # To hold host clients
    self.host_clients = {}
    self.host_config = host_config if host_config else {}
    self.retry_delay = retry_delay
    self.cmds = None


# 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 __init__(
    self,
    hosts,
    user=None,
    password=None,
    port=None,
    pkey=None,
    allow_agent=True,
    num_retries=DEFAULT_RETRIES,
    timeout=120,
    pool_size=10,
    host_config=None,
    retry_delay=RETRY_DELAY,
):
    if isinstance(hosts, str) or isinstance(hosts, bytes):
        raise TypeError(
            "Hosts must be list or other iterable, not string. "
            "For example: ['localhost'] not 'localhost'."
        )
    self.allow_agent = allow_agent
    self.pool_size = pool_size
    self.pool = gevent.pool.Pool(size=self.pool_size)
    self.hosts = hosts
    self.user = user
    self.password = password
    self.port = port
    self.pkey = pkey
    self.num_retries = num_retries
    self.timeout = timeout
    # To hold host clients
    self.host_clients = {}
    self._host_clients = {}
    self.host_config = host_config if host_config else {}
    self.retry_delay = retry_delay
    self.cmds = None