Wait to finish command executed with Python Paramiko

I wrote this code in Paramiko:

ssh = SSHClient()
ssh.set_missing_host_key_policy(AutoAddPolicy())
ssh.connect(hostname, username=user, password=passwd, timeout=3)

session = ssh.invoke_shell()
session.send("\n")

session.send("echo step 1\n")
time.sleep(1)

session.send("sleep 30\n")
time.sleep(1)

while not session.recv_ready():
    time.wait(2)

output = session.recv(65535)

session.send("echo step 2\n")
time.sleep(1)

output += session.recv(65535)

I'm trying execute more commands on my Linux server. The problem is my Python code not wait to finish execute command, for example if I'm try to execute sleep 30, the Python not wait 30 seconds for finish execute commands. How can resolve this problem ? I tried with while recv_ready(), but it still does not wait.

Use exec_command: http://docs.paramiko.org/en/1.16/api/channel.html

stdin, stdout, stderr = ssh.exec_command("my_long_command --arg 1 --arg 2")

The following code works for me:

from paramiko import SSHClient, AutoAddPolicy
import time
ssh = SSHClient()
ssh.set_missing_host_key_policy(AutoAddPolicy())
ssh.connect('111.111.111.111', username='myname', key_filename='/path/to/my/id_rsa.pub', port=1123)
sleeptime = 0.001
outdata, errdata = '', ''
ssh_transp = ssh.get_transport()
chan = ssh_transp.open_session()
# chan.settimeout(3 * 60 * 60)
chan.setblocking(0)
chan.exec_command('ls -la')
while True:  # monitoring process
    # Reading from output streams
    while chan.recv_ready():
        outdata += chan.recv(1000)
    while chan.recv_stderr_ready():
        errdata += chan.recv_stderr(1000)
    if chan.exit_status_ready():  # If completed
        break
    time.sleep(sleeptime)
retcode = chan.recv_exit_status()
ssh_transp.close()

print(outdata)
print(errdata)

Please note that command history cannot be executed with ssh as is. See example here: https://superuser.com/questions/962001/incorrect-output-of-history-command-of-ssh-how-to-read-the-timestamp-info-corre