Change master audio volume in Linux using python.

change_vol.py

import subprocess

def get_master_volume():
	proc = subprocess.Popen('/usr/bin/amixer sget Master', shell=True, stdout=subprocess.PIPE)
	amixer_stdout = proc.communicate()[0].split('\n')[4]
	proc.wait()
	find_start = amixer_stdout.find('[') + 1
	find_end = amixer_stdout.find('%]', find_start)
	return float(amixer_stdout[find_start:find_end])

def set_master_volume(volume):
	val = volume
	val = float(int(val))
	proc = subprocess.Popen('/usr/bin/amixer sset Master ' + str(val) + '%', shell=True, stdout=subprocess.PIPE)
	proc.wait()

print("Current volume: ", get_master_volume())
set_master_volume(0)
print("Current volume (changed): ", get_master_volume())
set_master_volume(50)
print("Current volume (changed): ", get_master_volume())

In ubuntu 20.04 only following works:
amixer_stdout = str(proc.communicate()[0],'UTF-8').split('\n')[4]

Nice Work ❤️