Traceback (most recent call last):
  File "/home/jakob/.virtualenvs/copper/bin/bpython", line 11, in <module>
    sys.exit(main())
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsies.py", line 190, in main
    exit_value = repl.mainloop()
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsies.py", line 125, in mainloop
    self.process_event_and_paint(e)
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsies.py", line 89, in process_event_and_paint
    self.process_event(e)
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsiesfrontend/repl.py", line 584, in process_event
    return self.process_key_event(e)
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsiesfrontend/repl.py", line 711, in process_key_event
    self.on_enter()
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsiesfrontend/repl.py", line 794, in on_enter
    self.push(self.current_line, insert_into_history=insert_into_history)
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsiesfrontend/repl.py", line 1058, in push
    self.run_code_and_maybe_finish()
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsiesfrontend/repl.py", line 1061, in run_code_and_maybe_finish
    r = self.coderunner.run_code(for_code=for_code)
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsiesfrontend/coderunner.py", line 136, in run_code
    request = self.code_greenlet.switch()
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/curtsiesfrontend/coderunner.py", line 178, in _blocking_run_code
    unfinished = self.interp.runsource(self.source)
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/repl.py", line 160, in runsource
    filename, symbol)
  File "/usr/lib64/python3.5/code.py", line 75, in runsource
    self.runcode(code)
  File "/usr/lib64/python3.5/code.py", line 95, in runcode
    self.showtraceback()
  File "/home/jakob/.virtualenvs/copper/lib/python3.5/site-packages/bpython/repl.py", line 215, in showtraceback
    l[len(l):] = traceback.format_exception_only(t, v)
  File "/usr/lib64/python3.5/traceback.py", line 136, in format_exception_only
    return list(TracebackException(etype, value, None).format_exception_only())
  File "/usr/lib64/python3.5/traceback.py", line 439, in __init__
    _seen.add(exc_value)
TypeError: unhashable type: 'ParseError'

import parsley

grammar = """
name = <letter letterOrDigit*>
"""

parser = parsley.makeGrammar(grammar, {})
parser("3").name()