Description:
sshuttle invoked with:
sshuttle -vv --ssh-cmd "$SSH_CMD" --dns -r myuser@myhostname.com:2222 172.42.0.0.0/16

gives:
Starting sshuttle proxy.
firewall manager: Starting firewall with Python version 3.8.3
firewall manager: ready method name nat.
IPv6 enabled: None
UDP enabled: False
DNS enabled: True
User enabled: False
Binding redirector: 12300
TCP redirector listening on ('127.0.0.1', 12300).
TCP redirector listening with <socket.socket fd=5, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 12300)>.
Binding DNS: 12300 12299
DNS listening on ('127.0.0.1', 12299).
DNS listening with <socket.socket fd=7, family=AddressFamily.AF_INET, type=SocketKind.SOCK_DGRAM, proto=0, laddr=('127.0.0.1', 12299)>.
Starting client with Python version 3.8.3
c : connecting to server...
c : executing: ['ssh', '-o', 'IdentitiesOnly=yes', '-i', './foo.pem', '-p', '2222', 'myuser@myhostname.com', '--', '/bin/sh -c \'P=python3; $P -V 2>/dev/null || P=python; exec "$P" -c \'"\'"\'import sys, os; verbosity=2; sys.stdin = os.fdopen(0, "rb"); exec(compile(sys.stdin.read(1279), "assembler.py", "exec"))\'"\'"\'\'']
c : > channel=0 cmd=PING len=7 (fullness=0)
load pubkey "./foo.pem": invalid format
server: assembling u'sshuttle' (88 bytes)
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "assembler.py", line 18, in <module>
TypeError: module.__init__() argument 1 must be string, not unicode
c : fatal: server died with error code 1


Additional info:
sshuttle 1.0.2-1