ls fails to return content for none root directories

[R-Sommer]

Describe the bug

Method ls raise FileNotFoundError when trying to get other directories than root

To Reproduce

#!/usr/bin/python3 -u

import technisat

ts = technisat.Technisat()

try:
    ts.connect("192.168.1.2", 2376)
except Exception as e:
    print(e)
    exit(1)

print(ts.ls(directory="/recordings"))

ts.disconnect()

quering root directory works as expected

#!/usr/bin/python3 -u

import technisat

ts = technisat.Technisat()

try:
    ts.connect("192.168.1.2", 2376)
except Exception as e:
    print(e)
    exit(1)

print(ts.ls())

ts.disconnect()

Output
{'recordings': {}, 'music': {}, 'pictures': {}, 'video': {}}

BUG hint

Line 145 if d in current_dir fails since current_dir contains an empty dict.