Polymode with Python Emacs crash

test-mode.el

(require 'polymode)

(defcustom pm-host/test
  (pm-bchunkmode "test"
		 :mode 'fundamental-mode)
  "Test host chunkmode"
  :group 'hostmodes
  :type 'object)

(defcustom  pm-inner/pytest
  (pm-hbtchunkmode "python"
                   :head-reg "^begin .*\.py"
                   :tail-reg "^end .*\.py"
		   :mode 'python-mode)
  "Python chunk."
  :group 'innermodes
  :type 'object)

(defcustom pm-poly/test
  (pm-polymode-one "pytest"
                   :hostmode 'pm-host/test
                   :innermode 'pm-inner/pytest)
  "Polymode for Test."
  :group 'polymodes
  :type 'object)

(define-polymode poly-test-mode pm-poly/test)

(provide 'test-mode)

test.txt

This is some text

begin data test.py

      def hello():
      	  print "hello"  

end data test.py