Get IPs of all devices connected to local network (based on hostname) with python

this is definetly not duplicate.

I am doing an app and I need to find IPs of my devices. I know their name, and through their name I need to get their IP. Linux should be easy but I need cross platform attitude and so therefore I use python.

I already know solution:

import socket
socket.gethostbyname('pc_name')


If I know solution, why I am asking? Well give me moment, because I am not getting stable results.

Situation:
I need to find IPs of several raspberry pi's that has same hostname - lets say:

Raspberry pi device 1: Hostname: 'MyPi', Local IP: 10.0.0.33

Raspberry pi device 2: Hostname: 'MyPi', Local IP: 10.0.0.34

Raspberry pi device 3: Hostname: 'MyPi', Local IP: 10.0.0.35


So according to socket documentation(If I read it correctly),

socket.gethostbyname('MyPi')


returns only one IP, HOWEVER

socket.gethostbyname_ex('MyPi')


should return all IPs for the particular hostname.

I simulated the situation at home and the results were very unsatisfying.
I called my raspberry pi as my Android phone: 'Galaxy-J5-2016'. To make sure I tried to find them by address:

>>> socket.gethostbyaddr('10.0.0.33')
('Galaxy-J5-2016', , ['10.0.0.33'])
>>> socket.gethostbyaddr('10.0.0.34')
('Galaxy-J5-2016', , ['10.0.0.34'])


Good , they exist. When I tested it before writing here, I even got one result if I searched

socket.gethostbyname('Galaxy-J5-2016')


BUT now I dont find anything even if I try

socket.gethostbyname_ex('Galaxy-J5-2016')


Both above commands simply wait without response and then respond with this:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
socket.gaierror: [Errno 11001] getaddrinfo failed


Another phenomena occured: When I try lastly mentioned command on my work laptop(Even though my work PC doesnt share hostname with any other computer),

>>> socket.gethostbyname_ex('WORK_PC.DOM1.DOM2')
('WORK_PC.DOM1.DOM2', , ['172.xx.xx.1', '10.0.xx.1', '172.xx.xx.241',
'192.xx.xx.1', '192.xx.xx.1', **'10.0.0.41'**])


Interestingly 10.0.0.41 is local ip address that my WORK PC has right now at home (The rest seems are from network at my job).

In other words: I have two machines with same Hostname and I get zero or only one IP adress and my work PC is just one MACHINE and i get several IPs of the same machine and these IPs so to say are not even from the actual local network)

PS (In case you will advice me 'arp -a'): general command 'arp -a' is useless as it shows all local IPs that were in recent contact with the command-machine. So I need to ping the particular devices to see them listed in arp -a command.

PS2: Also I dont want any solution that requires going through all IPs. This solution is very slow as pinging IP that doesnt exist will result in several seconds timeout. 255 IP + timeout is not good.

Honestly, If there exist python command to immediatly list all devices connected to Local Network, its enough... But I didnt find anything like this.

Am I doing something wrong? Can you direct me?

Thanks in Advance

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