/usr/share/debhelper/autoscripts/prerm-pyclean is in python 2.7.5-5ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8  | if which pyclean >/dev/null 2>&1; then
	pyclean -p #PACKAGE# #ARGS#
else
	dpkg -L #PACKAGE# | grep \.py$ | while read file
	do
		rm -f "${file}"[co] >/dev/null
  	done
fi
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