Weird new SIGPIPE exception

[pfuntner]

I wrote a new tool that uses the SIGPIPE handler to exit when the signal is sent but I got a weird error:

$ git-new-files | head
bin/git-new-files
bin/rotate
bin/gityup.py
bin/ansible-host-data
bin/ansible-json
bin/add-python-debugging
bin/grep-matrix
bin/inventory-to-config
bin/git-files
bin/git-clone
Exception ignored in: <module 'threading' from '/usr/lib/python3.6/threading.py'>
Traceback (most recent call last):
  File "/usr/lib/python3.6/threading.py", line 1279, in _shutdown
    def _shutdown():
  File "/home/mrbruno/bin/git-new-files", line 24, in <lambda>
    signal.signal(signal.SIGPIPE, lambda signum, stack_frame: exit(0))
  File "/usr/lib/python3.6/_sitebuiltins.py", line 26, in __call__
    raise SystemExit(code)
SystemExit: 0
$